Monday, July 13, 2015

Get "Mean" with Noise

The two common ways to deal with digital noise are: shoot at a low ISO or apply noise reduction in post-processing. Traditionally when shooting landscape scenes, a tripod and low ISO went hand-in-hand and noise wasn't usually an issue, especially with low-noise cameras. Nevertheless, situations arise that require high ISOs to combat wind or curb excessive exposure times in low light. Furthermore, shooting HDR or using image enhancement plugins (for example, Nik’s Color Efex Pro), can exaggerate even minor noise to where it becomes objectionable. 

When dealing with noise during post-processing, Photoshop, Camera Raw, and Lightroom offer excellent noise reduction filters. There are also Photoshop plugins, such as Nik’s Dfine, that specialize in reducing noise. All these filters do a good job at removing noise while hardly effecting edge sharpness. The devil, though, is in the details where subtle textures and fine details may wash out. 

The “Mean” Approach
Another approach is to simply take redundant exposures and average them in Photoshop CC. In fact, some cameras do this internally, but only as a JPEG output. In any case, this nondestructive approach substantially reduces noise without effecting any part of the image. The only restriction, obviously, is the scene must be completely static during the exposures. 

Averaging Procedure
  1. Shoot two to four redundant exposures (four being ideal) using, obviously, a tripod. Best to shoot at manual exposure and focus, but you probably can get away with using auto.
  2. After processing the raw files in Camera Raw (and skipping any noise reduction), from Bridge select the files and click: ToolsPhotoshopLoad Files into Photoshop Layers. You can also load the files into stacks directly within Photoshop by clicking: FileScripts → Load Files into Stack…browse and select files.
  3. In Photoshop, select all the layers and click: LayerSmart ObjectsConvert to Smart Object.
  4. After the conversion is complete, you have a single Smart Object  layer. Now click: LayerSmart ObjectsStack ModeMean. You can also select Medium which is the center value, but the results are likely to be similar.
Averaging versus Noise Filters
To see if this approach is worth the added inconvenience of shooting multiple frames, I used a dimly-lit indoor scene to compare between frame averaging, noise filters, and no filtering. The longest exposure (at ISO 100) was 2.5 sec at f/5.6. That’s 20 sec at f/16, which is a common exposure setting for golden light shooting. This test scene allowed me to scrutinize text and barcodes for edge sharpness and the woodgrain pattern for fine-detail rendering. I also examined the blacks and deep shadows to determine the extent of grain patterns.  

I made test shots at ISO 100, 800, and 1600. I used a Canon 5D Mark II, which is a reasonably low-noise camera, but isn't par with the latest full-frame cameras. For the ISO 800 and 1600 shots, I compared them with no noise filtering, frame averaging, and using the Dfine noise reduction plugin. I first compared two different swatch areas from the scene at 400% to gauge the relative differences. Then I printed a large section of the image at the equivalent size of a 16x24 inch print (at 234 ppi, the best my camera can do at that size) and visually assessed the image quality. 

Results at 400%
Below is the test scene. Below that are the 400% zoomed swatch samples taken from the black notebook and a section of woodgrain (see red circles). For comparison, the left image in all the samples is the ISO 100 shot without noise filtering. All middle samples are ISO 800 and ISO 1600 on the right. You can click on the images for a better view.

Test Scene: Red circles indicate the location of the 400% enlargements below.


No noise filtering

Left-to-Right: ISO 100, 800, and 1600, all with no noise reduction.
Above, you see the expected increase in grain at the higher ISOs. Though you can perceive some slight noise in the ISO 100 black patch, at this level of zoom it is insignificant enough to be considered nonexistent. 

Nik's Dfine Plugin

Left-to-Right: ISO 100 without noise reduction, ISO 800 and 1600 with Dfine plugin.
In the above black patches, the Dfine-filtered ISO 800 and 1600 samples yielded a purer black than the unfiltered ISO 100 patch. However, this came at a price you can see in the woodgrain samples. By ISO 1600, the woodgrain structure and fine detail is obliterated to a noticeable degree. 

There is some irony to this. Without divulging what to look for, a person may prefer the Dfine rendering over the virtually noiseless ISO 100 sample because the woodgrain has a more smooth and natural look. This illustrates how subjective all this can be. Nevertheless, sticking to "technically" best, elsewhere within the test scene Dfine tended to blur out other fine detail. In short, Dfine's effectiveness excels at low-frequency and gradually diminishes towards the higher frequencies (though edge sharpness wasn't noticeably affected).

Four-Frame Averaging

Left-to-Right: ISO 100 without noise reduction, ISO 800 and 1600 with 4-frame averaging.
Averaging four exposures produced the best balance between significant noise reduction and maintaining detail without degradation. Surprisingly, the black patches were all similar in appearance. Furthermore, the ISO 800 woodgrain patch rivaled the non-averaged ISO 100 patch, and the ISO 1600 was only a little worse off.

16x24 Inch Print Results
The above 400% zoomed patches are like looking at an ant under the microscope: first a scary monster, but then with the naked eye, an innocent bug. Observation made at this high a zoom level don't necessarily translate into the final print. 

I used my Epson Pro 3800 at 1440 dpi on Epson Premium Luster paper to print a large swath of the test image at an equivalent 16 x 24 inch print size. I viewed the prints from nose-length to arm-length, which the later is still technically too close to view a print this size (minimum distance is 29-inches). But bowing to human nature, I know many can't resist judging prints of any size that way. I did not, however, judge the prints using a magnifier since that would be meaningless. All test images were unedited except for the indicated noise filtering and sharpening for output using Nik's Sharpener Pro 3. 

Edge Sharpness
Resolution should suffer as the ISO increases, but all the samples, including the heavy-handed Dfine filter, were nearly equal in preserving  the resolution of small text (on the aerosol can) and UPC bar codes. Instead, image casualties were largely confined to the fine details in the woodgrain and visible noise grain in the dark shadows.

Fine Detail Rendering
ISO 100
  • Without requiring any noise filtering, the ISO 100 print is visually noise free. To validate that observation, I averaged  four frames shot at ISO 100 and compared it to the single-frame version. I couldn't detect any difference. The ISO 100 print was the gold standard I used to compare the rest.
ISO 800
  • No noise filtering: Some noise is visible when compared to the ISO 100 shot. Most noticeable was the slight breakup in the woodgrain detail. Noise was also detected in the deep shadows, but surprisingly the blacks all looked about the same.
  • Dfine noise filtering: The Dfine print is totally eradicated of any visible noise, but at the cost of rendering the woodgrain with a "creamy" look. However, as I commented before, without the ISO 100 print to compare, most (even critical) observers would likely not pickup on that flaw. 
  • Averaging frames: This was  the undisputed champ. Any detected differences between it and the ISO 100 print were more imagination that reality. 
ISO 1600
  • No noise filtering: Considerably more noise is evident and even the pure-black areas started to show slight noise. 
  • Dfine noise filter: The Dfine print, as with the ISO 800 Dfine print, was devoid of any noticeable noise. However, the "creamy look" of the woodgrain was more apparent. Even if most viewers still couldn't pickup on this defect, I think most fine-art printers would cringe at this much fine-detail loss. 
  • Averaging frames: Again the champ. Compared to the ISO 100 print, noise was only slightly more noticeable and I doubt even the most critical printer would find it objectionable. 
What about Photoshop and Camara Raw Noise Filters?
To keep this article short I excluded showing Adobe's noise filter examples. If I did, you'd see the results to be roughly between averaging and Dfine. One interesting observation was when I tried to push the Photoshop filter to same noise-reducing level as Dfine, the red graphics and red lettering on the aerosol can were interpreted as color noise and either were smeared or completely desaturated. These aren't typical image characteristic in most landscape scenes so, in practice, this probably isn't a common problem. Regardless, if you need to deal with seriously noisy images, Dfine may be the best tool of the bunch.

First a reality check. To keep things in perspective, all the preceding critical comments were more academic that meaningful, especially to the average Joe. In the real world, a great image is all that matters and nobody cares about a few scattered areas of noise grain, even if they notice it. When I was examining the 16x24 test prints, I kept asking myself if I were handed these prints without explanation and asked to find any differences, how long would it take me to see any, if I could at all! The simple fact is, if someone is noticing the noise, then the picture wasn't all that hot to begin with.

That said, I have nonetheless convinced myself that frame averaging is the best way to lower noise. From a practical standpoint, frame averaging at ISO 800 produced essentially the equivalent image quality as at ISO 100. Even at ISO 1600, the results were sufficient to satisfy most fine-art connoisseurs. The big letdown, unfortunately, is most situations requiring higher ISOs usually mean frame averaging isn't practical. You obviously can't have any subject movement and that makes it useless when increasing ISO to combat wind. So when is it useful, at least for landscape photography? Obviously if your camera is inherently noisy, this helps a lot. But I may find it useful when shooting HDR.

A case in point is when my longest exposure within a bracketed HDR series exceeds my camera's maximum shutter time of 30-seconds. This is not uncommon when shooting during the last vestige of evening light with a small aperture for greater depth-of-field. Instead of hassling with the bulb setting, I would normally bump up the ISO and deal with any noise in post-processing. Now I'll shoot between two to four consecutive series and average them without suffering any noise penalty. In fact, I may do this as a matter of course for all HDR shots. HDR software, by its nature, can at times greatly exaggerate even minuscule levels of noise. Ditto to some image enhancement software, such as Nik's Color Efex Pro. As a rule, I always strive to make my files as squeaky clean as possible, and now frame averaging is another tool to help with that.

Bonus Feature!
Here's a bonus feature with frame averaging that hasn't anything to do with noise. Did you ever long to create those dreamy water scenes taken with extremely long shutter times? Usually, you need a strong neutral density filter (e.g. ND9) to create those long exposures. But what if you don't have an ND filter? Instead, use as long an exposure time you can muster and then take repeated exposures spaced over a suitable time. Now, use the frame averaging in Photoshop CC and, voilĂ , you have a dreamy waterscape.

Wednesday, May 13, 2015

Lightroom CC's New Panorama Merge

Beside Lightroom CC’s new HDR Merge feature (see previous post below), Adobe has added a panorama merge function. And what makes this significant is that it’s better than Photoshop's panorama merge function. The reason is you can edit the stitched image in the Develop module as a raw file. In Photoshop, you edit only with the usual gamma-corrected image file. Raw files provide more editing latitude; and, as a rule, you should do as much possible of your editing with the raw converter before transitioning to Photoshop. Admittedly, that advantage may not always be apparent when dealing with a properly exposed image that doesn’t have problems in the dark tones or highlights. But if you have highlights or shadows that you need to dig out any detail from, it's better to do that in the raw converter. I’ll demonstrate that shortly with a few example images.

The panorama merge function in Lightroom is a snap to use. Adobe has a short tutorial (click here) that explains everything, including how to do a HDR panorama merge. To test out this new feature, I compared a panoramic image created in both Lightroom and Photoshop of the Queen Anne Cottage in the Los Angeles County Arboretum. I also created a HDR panorama to see how well it performed. By the way, if the image seems vaguely familiar, remember the opening dialogue of a long-ago TV series: The plane! The plane!

Routine Panorama
I started with a  two-frame panorama that was properly exposed with little or no shadow and highlight problems. For the Photoshop version, I used the Camera Raw Filter and duplicated the same settings used in the Lightroom Develop module. In this example, the raw converter's advantage in Lightroom doesn't come into play that much. Both images are essentially identical, and this is likely the case for most evenly-lit and properly exposed panoramic images. 

All the panoramas were merged using the Cylindrical layout option, which I find is best for most my panoramas. However, you'll lose a portion of the image after cropping, and that's a problem if the scene was tightly framed. In that case, you may need to use the Reposition option in Photoshop, but for some reason that wasn't included in Lightroom. The problem with the Reposition option is its propensity to create artifacts, especially if the camera was tilted when panned. Photoshop has tools to deal with some artifacts and you can click here to read more about them. The best solution, though, is always allow plenty of crop room when composing a panorama.

Lastly, I noticed that the stitched panoramic file resulted in a .dng format (Adobe's open-standard raw file format) and not your camera's proprietary raw format. Not an issue for me since I convert all my Canon raw files to .dng anyway.

Lightroom CC Panorama Merge
Excellent results and no stitching artifacts.
Photoshop 2014 Panorama Merge
Both Lightroom and Photoshop are essentially identical.

Highlight and Shadow Recovery
In this example, I used a 3-frame panoramic shot of the same scene. One series was shot at +1.33EV overexposure and another at -1.33EV underexposure. This intentionally created some problematic highlights and shadows that I then attempted to extract detail from. The image below shows which highlights (blue-circled cottage roof) and shadows (red-circled palm trees) I worked on.

Highlight/Shadow Recovery
I'll demonstrate the recovery difference between Lightroom and Photoshop within the blue-circled
highlight area (cottage roof) and red-circled shadow area (between the palm tree trunks).
Highlight Recovery
In this example, the Develop module and Camera Raw Filter settings were identical. The Lightroom version has better overall contrast and detail in the highlights, plus better texture in the white plastic tarp. To read more why editing in raw is better, see my post on Exposing-to-the-Right. There, I discuss the advantages of a linear-data file (raw) versus a gamma-corrected file (Photoshop). There are other reasons too, such as a special highlight recovery algorithm in Adobe's raw converter.

Lightroom Highlight Recovery
Better overall contrast and detail, especially in the white tarp's texture.
Photoshop Highlight Recovery
Maybe a bit more fiddling in the Camera Raw Filter could even things 
up a bit more, but fundamentally, Photoshop just has less data to work with.
Shadow Recovery
At the dark end of the histogram, the differences are more noticeable. In the Photoshop version, I had to apply additional shadow recovery to the Camera Raw Filter in an attempt to even the difference. But in spite of the additional tweaking, the Lightroom version is still noticeably superior at rendering the shadow detail while the same detail in the Photoshop version is blocked up. In addition, the overall Photoshop image (including the shadow detail) was a little too contrasty. 

Lightroom's Shadow Recovery
Lightroom does a really a great job! Additional editing
could perk up the contrast and saturation a bit more
and still retain good shadow detail.
Photoshop's Shadow Recovery
 Blocked-up shadow detail and too much contrast,

HDR Panoramas
I didn't bother to compare the HDR panorama performance between Lightroom and Photoshop since Photoshop's 32-mode has gone squirrely in their latest 2014 version (at least on my computer). Nevertheless, I tested how well it worked in Lightroom, and the results were excellent. 

Now there are two ways to process a HDR panorama shot. You can stitch all the frames for each exposure, then combined them in HDR. Or, first combine the exposures for each frame segment in HDR and then stitch them into a panorama. However, only the latter will work in Lightroom, and for that matter, only in Photoshop and Photomatix 5 as well. The reason is when you stitch each exposure frame set, each set results in a slightly different size (by only a few pixels). That stops Lightroom and Photoshop dead in their tracks, and while Photomatix will merge the frames, it generates weird artifacts. Only HDR Efex Pro 2 seems to cope with the slightly different image sizes without a hiccup.

The reason I bring this up is because, intuitively, I prefer to combine the stitched panoramas in HDR. One reason is I worry that first combining each segment into HDR before stitching may produce slightly uneven results between the panoramic segments, especially in luminance. Any differences in luminance will become apparent in the sky after they're stitched. Of course, as already mentioned before, you can repair the artifacts in Photoshop, but who needs the hassle. But the biggest reason is I want the ability to fully edit the whole panorama in 32-bit mode. Yes, I could edit each segment in 32-big mode, but that's both awkward and may increase the chances of uneven frames. 

Nevertheless, simply merging each segment into HDR (without, of course, any additional editing in 32-mode) and stitching them into a panorama produced an excellent image, at least for this example. And as a consolation prize for losing the 32-bit editing capability, the stitched file at least remains a linear file. However, this image wasn't particularly challenging and a high-contrast sunrise or sunset scene may beg for 32-bit editing capability. Then the only recourse I can see is to stitch each exposure series in either Lightroom or Photoshop (probably doesn't matter which) and use HDR Efex Pro 2 to edit the entire image.

Lightroom HDR Panorama
Results were great with no artifacts (HDR or stitching) and even sky illumination. Highlight
and shadow details are excellent. A little more editing will brighten up the image even more.
The preceding discussion was as much about Lightroom's new panorama merge as why editing in raw is important. But I needed to emphasize the latter to illustrate how nifty the new Lightroom feature is. Does this replace Photoshop's panorama merge (aka, Photomerge)? I'd say pretty much so. I'm hard-pressed to think why you would ever want to circumvent editing in raw. If Lightroom's merge did create any stitching artifacts, you can still fix them in Photoshop after you completed the bulk of editing in Lightroom. The only reason I can see to use Photoshop is for the Reposition layout option; but proper composing should avoid that need.

Wednesday, May 6, 2015

Lightroom CC’s New HDR Merge

Lightroom CC has a new HDR feature that merges multiple exposures for 32-bit tone mapping within the Develop module. This mimics the existing 32-bit mode featured in Photoshop that merges exposures using HDR Pro, but tone maps in Camera Raw rather than in HDR Pro. (Click this link to see my previous post on Photoshop CS6's 32-bit mode.) Processing HDR files in Lightroom CC is very simple and rather my explaining it, just go to this link for a short Adobe tutorial. To test out Lightroom CC's new HDR mode, I compared it to Photoshop's 32-bit mode, HDR Efex Pro 2, and Photomatix Pro 5. (Note: Also new in Lightroom CC is a very promising panorama merge feature that I’ll report on later.)

Say It Ain't So Photoshop!
My expectations were that Lightroom and Photoshop would perform identically since, after all, they’re essentially the same software. Well, that expectation was sorta true. Lightroom seemed to perform similarly to the results I observed when I originally evaluated Photoshop C6’s new 32-bit mode. But something happened on the road to bigger-and-better. My evaluation this time was based on Photoshop CC 2014 (v2.2) — and now it's awful!  The biggest issue is the rendering of dark tones, but the rest of the image is also mediocre. I did find one similar complaint on the Internet. I don’t know if it’s a Mac-only problem, something unique to my configuration, or some boneheaded error on my part (anything is possible); but as it stands now, it’s essentially unusable.

Update: After upgrading to the new Photoshop 2015, the above problem vanished. Photoshop 2015 and Lightroom CC now appear equivalent in performance, as you would expect. Any comments hereon on Lightroom CC should apply equally to Photoshop 2015's 32-bit mode.

I'll show two example landscape scenes processed in Lightroom, Photoshop, and HDR Efex Pro (and Photomatix 5 on the second scene). First, I'll show how each image initially emerged from the HDR merge process. For HDR Efex, that means how the images appeared right out of the oven before any additional 32-bit editing. For Lightroom and Photoshop, however, it was necessary to make major adjustments to all the exposure controls to get the histogram into a decent starting point. This is normal and shouldn’t be construed as a performance flaw. Next, I’ll show the results after additional 32-bit editing and final touchups in Photoshop with a little help from Color Efex Pro. Note: I didn't spend much time on color balance, so ignore any color differences which aren't necessarily a characteristic of any particular process.

Scene One: High-Contrast Daylight Scene in Bryce Canyon National Park
Lightroom CC
The initial HDR merge in Lightroom produced acceptable results, but it took radical increases in all the exposure sliders to get to a decent starting point. Though you have a workable image, the extreme exposure adjustments leave less editing latitude in the highlights and shadows during subsequent 32-bit editing. Nevertheless, the final image rivals HDR Efex Pro, but lacks the crisp contrast and finer detail in the highlights and shadows. Image quality is often more subjective than technical, so you may still prefer the Lightroom rendering over HDR Efex Pro. However, I feel HDR Efex Pro has the edge.

Lightroom Raw Merge: All the image detail is there, but it
took pushing the exposure controls nearly to their stops. 
Lightroom After Final Editing: Satisfying results
with a natural appearance that adequately captured
detail in the highlights and shadows.
Photoshop 2014
In a word: yuck! After merging in HDR Pro, the image is oversaturated, too dark, and simply garish. Previously in Photoshop CS6, the results would have been similar to Lightroom's. I had to throw everything (including the kitchen sink) at it in both Camera Raw and Photoshop to eventually eke out a presentable image.

Photoshop CC 2014 Raw Merge: Too dark, 
oversaturated, and poor detail in the shadows.
Photoshop CC 2014 After Final Editing:
Better than nothing? Yeah, but not by much.
HDR Efex Pro 2
At first blush the HDR Efex Pro raw output seems less impressive than the Lightroom version; except, the exact opposite is true. All the highlights and shadows are well defined within the histogram, which is what you need to have maximum editing latitude in those tonal areas. The final image needed the least editing gymnastics and produced a nicely toned and reasonably nature appearance.
HDR Efex Pro 2 Raw Merge: The champ at
capturing all the highlights and dark tones. 
HDR Efex Pro After Final Editing: Great results with plenty of
editing latitude to reshape it to whatever suits your taste.
Scene Two: Sunrise at Joshua Tree National Park
Lightroom CC
Again, the merged image gives you a decent starting point. And this time, Lightroom really gives HDR Efex Pro a run for its money in the final image. HDR Efex Pro still has the advantage in better detail rendering and midtone contrast, but loses in two respects. A systematic problem with HDR Efex Pro has always been two irritating flaws. The first is emphasizing noise, and the second is halo artifacts along high-contrast edges. Both are correctable in Photoshop, but that's an unwelcomed nuisance. All the processes are susceptible to this to some degree, but HDR Efex Pro is most prone. So, would I choose  Lightroom's version over HDR Efex Pro? Not yet—keep reading.

Lightroom Raw Merge: Ditto to previous example.
Also, very low in noise and halo artifacts.
Lightroom After Final Editing: Excellent
results with a natural "traditional photo look".
Photoshop 2014
There's no point in beating a dead horse. The results are just as disappointing as in the Bryce Canyon photo.
Photoshop CC 2014 Raw Merge: Badly blocked up shadows.
Photoshop CC 2014 After Final Editing: In a word: unacceptable.
HDR Efex Pro 2
The merged results are excellent with plenty of editing latitude. The final results also don't disappoint (except for slightly more noise and halo artifacts, which you can observe between the mountain ridge and sky). Probably I would still pick this photo over Lightroom after fixing the artifacts and working the sky a little better (also note that this image needs some repair for lens flare that I didn't bother with in any of these examples). But in any case, I would be very satisfied with either versions. 

HDR Efex Pro 2 Raw Merge: Repeat performance.
HDR Efex Pro 2 After Final Editing: Some annoying halos
and slightly more noise (all which can be fixed in Photoshop)

Photomatix 5
To spice up the comparison, I included a final image done in Photomatix 5 using the new Contrast Optimizer. I went back and forth on this, but concluded that Photomatix edged out the other two, but only for this particular image. The results are similar to HDR Efex Pro, but without the slight increase in noise and halo artifacts. Admittedly, I could go back and re-tweak HDR Efex Pro; but Photomatix quickly produced an excellent result for this particular image with little effort, so I'll give it the crown mainly for that reason.

Photomatix 5 After Final Editing: Unless I go back and fiddle
more with the HDR Efex Pro example, I'd say this one is the winner.
No (or barely) halo problems or noise increase.
If I had to describe the basic character of each, I would say that HDR Efex Pro excels in rendering detail in highlights and shadows, has snappy midtone contrast, and has powerful editing tools. The better rending does come at the cost of a very slight "HDR look" (i.e, slightly unnatural or surrealistic) and, of course, the already mentioned noise and halo artifacts. Lightroom has a more soft and natural appearance—more towards a traditional photo look. If that more subdued appearance is better or not, I'll leave that to your personal taste. Also, the powerful editing tools in the Develop module (or Camera Raw once Photoshop gets its act together) are a big plus, but that's slightly diminished by having to push many of the exposure adjusts to their limit. Photomatix 5 (specifically Contrast Optimizer) is roughly in-between, though a bit closer to HDR Efex Pro. It's editing ability is the most limited, but at least it's also the simplest. In spite of that, it can still bang out a stunning image. For more information on Photomatix 5 (specifically Contrast Optimizer), click this link to a previous post I wrote comparing Photomatix 5 and HDR Efex Pro 2.

If you're interested in more information, please visit my posts on Photoshop's 32-bit mode and Photomatix 5. I believe the comments and conclusions I made there are still relevant. However, for the Photoshop 32-bit mode article, substitute the name "Lightroom CC" for "Photoshop". Given how poorly Photoshop 2014's HDR Pro performed, I'm sure it will eventually be fixed. But for now, it doesn't matter anyway. If you are using CS6, then you're not affected. If you're on the Adobe subscription plan, then you have Lightroom. In either case, you have a viable HDR processor that should satisfy a good portion (and maybe most) of your HDR needs. 

But if you are a heavy user of HDR, I still recommend that you also have either HDR Efex Pro 2 or Photomatix 5. In fact, I strongly recommend you have both. In my experience, there can be erratic behavior in file merging in any of the processes. Even HDR Efex Pro, which is my primary choice, has on occasion gone inexplicably bonkers on an image. Remember, you can't preview your HDR images out in the field. Unless you shot a backup frame using just a graduated neutral density filter (something I always recommend), you may be at risk of losing a once-in-a-lifetime shot unless you have more than one way to process your HDR images.

Sunday, March 29, 2015

iMac 5K Retina: Photographer’s First Impressions

This post may interest only Apple desktop users or anyone else contemplating upgrading to the new iMac 5K Retina. I just upgraded from a late-2009, 21-inch iMac to the new iMac 5K Retina with i5 processor and 16GB memory. The following are comments and first impressions from a photo-editing perspective. 

iMac 5K Retina
The new 5K iMac was introduced in late 2014. It has a 27-inch Retina display with 5120 x 2880 resolution. Aside from the display and an upgrade to Thunderbolt 2 (vs. 1), the inners are essentially the same generation as the rest of the iMac line. However, a side-by-side comparison between the 5K and the older display will knock your socks off. The 5K can display an actual-size 12 x 18 inch image at 218 ppi, which is printer output quality! The older 21.5-inch and 27-inch iMacs are half that resolution. 

Intel i5 vs. i7?
I agonized over this for a long time. Ordinarily, I would have opted for the i7 since the cost difference is only $250 more. The i7’s hyper threading feature can improve performance on some (but not necessarily all) photo-editing algorithms. My hesitation was the power dissipation of the i7 when running full bore. According to Apple's specs, the i7 dissipates over a 100 watts more than the i5 (though at idle both processors are about the same). Before purchasing the 5K, I researched the web to ferret out any weaning issues with the new 5K. A common complaint I saw concerned internal high temperatures of the i7 and the annoying fan noise that resulted. 

I also compared some Photoshop performance benchmarks and the i7's performance was only marginally better than the i5. From that I assumed (and I could be easily wrong) that Photoshop doesn't benefit much from the i7's hyper threading feature. However, I’m a heavy user of the Nik Collection plugins and, according to Nik, they can benefit from the hyper threading; but by how much is unknown. Based on averaging various Geek benchmarks, I’d estimated that the i7 may improve performance by roughly up to 30%. That’s significant, but not particularly earth-shaking, so I decided to play it conservatively (from a long-term reliability perspective) and opted for the i5.

Apple has migration software to transfer all of  your old computer's software to the new one. I elected not to use it because I was upgrading from Maverick to the latest Yosemite OS. I rather reinstall all of my software applications with the latest versions to avoid any problems with the new OS. I was also overdue for a good housecleaning anyway. As for my user files, I keep those on a separate drive and merely connected it to the new computer.

Besides software, I have two FW800 drives and an old FW400 flatbed scanner. I wanted to keep the Fire Wire bus to save on USB ports, but I was a bit concerned (especially with the older scanner) that the new Thunderbolt might prove problematic. It was a needless worry: every thing worked perfectly. You will need a Thunderbolt to Fire Wire adapter ($29), otherwise it's all plug-and-play.

Performance Improvement
My point of reference is my 5-year old, 2-core iMac; but if you’re upgrading from a similarly aged (or 2-core) machine, then your experience should be similar. Using files from my Canon 5D MkII (21 megapixels), I timed various Photoshop, HDR Efex Pro, and Color Efex Pro processes. The results confirmed the various Geek benchmarks that I researched, which is an average 2.2x speed improvement. 

Next, I downloaded a 50-megapixel jpeg file from Canon's new 5DS camera. I performed a single Tonal Contrast adjustment in Color Efex Pro, which caused my old iMac to churn for some time. But on the 5K, with the larger file, the performance increase was now almost 3x. On top of all this, the Fusion Drive (a SSD and mechanical drive hybrid) adds considerable snappiness to boot-ups, shutdowns, and program launchings.

Besides the previously mentioned heating issue I found on the Internet, another common complaint was from some Lightroom users about extremely slow response times in the Develop module. There was even a complaint about Photoshop (that mentioned Selective Color in particular). Apparently the thinking was the 5K's pixel updating was too taxing. I don't use Lightroom, but I was concerned that the equivalent Camera Raw may be similarly effected (though no one complained specifically about Camera Raw). In any case, I quickly performed a few adjustments in Lightroom as well as PS's Selective Color, and they all performed normally in my opinion. 

As a last note, there was one mystifying observation. Photoshop’s Smart Sharpen on my old iMac took forever to complete, which always seemed odd for a sharpening routine (“smart” or otherwise). On the 5K, Smart Sharpen performs in the wink-of-an-eye — go figure.

Monitor Calibration
I was able to successfully calibrate my 5K using the Spyder 3 Elite. There is no problem lowering the display's luminance to a level necessary for calibration. (First generation iMacs were too bright and couldn't be calibrated.) I use a level of 120 cd/m2, but you can dim it lower if necessary. Gamut is still sRGB and the results are pretty much the same as my older  iMac. Note: make sure the 'Automatic adjust brightness' box is unchecked in the System Preference monitor setup.

Monitor Experience
Text looks like offset printing! But, some fonts are now a tad smaller and I found it necessary to move in a little closer to read them (probably not an issue for younger eyes). That resulted in a little more neck craning to take in the whole screen (IMAX lovers will be use to it). The high resolution also allows you to better assess a print in terms of noise and sharpness when displayed at actual size. However, I found it best to judge the appearance of an inkjet print output before sharpening. The high-resolution display may show more of the exaggerated sharpening effect that is necessary to compensate for the inkjet’s inherent blurring. In other words, a displayed sharpened image won't look like the printed output. (That assumes, of course, the image was properly sharpened in the first place.)

The appeal of the Retina display has more to do with the “wow” factor than actually helping you produce a better image. It’s better software and the honing of your editing skills that ultimately matter. In the end, I’d have to say that a Retina display falls more in the luxury rather than necessity category. Furthermore, giving the iMac’s rather languid performance improvements over the last few years, you can probably cruise along with your current machine for a while longer without being denied any significant productivity improvement.

So, if you’re hot for the latest-and-greatest computer and your pockets are bulging with money then, by all means, go for the 5K. But if money is tight and your computer suddenly exploded into a mushroom cloud, you’ll do just fine with any of the lower-end iMacs. Your edited pictures will look the same no matter which machine you use. (Note: I would, however, not recommend the $1,099 budget 2-core iMac. You want a higher-end model to keep up with newer software and the next-generation of higher-pixel cameras.)

Thursday, January 1, 2015

Photoshop's New 'Focus Area' Tool

One advantage of Adobe’s subscription service is you always have the latest-and-greatest version of Photoshop. As such, you need to be diligent in keeping up with the constant update of new features or else, as in my case, you’ll miss out on a potentially dandy feature. Usually, Photoshop displays a splash screen at start-up to inform you of new features. But I always seem to be in a rush and I more often dismiss the tutorial than read it. In Photoshop CC (2014), Adobe added a new feature called Focus Area, which I’m embarrassed to say I didn’t know existed until I stumbled on it. (In my defense, I reviewed the splash screen that listed all the new 2014 features and I couldn’t find anything about Focus Area. I’m sure it’s buried somewhere, but I couldn’t find it.)

“Mask” of the Red Death
Creating masks or selections is often the most frustrating task you’ll ever do in Photoshop. A classic example is trying to create a selection around someone’s frizzled hair. Even if all you do is landscape photography, there'll always be a need to create a mask at some point in time. Fortunately, Photoshop has added features over time to help out with this problem. You have Pen Tool, Magnetic Lasso, Magic Wand, Color Range, Refine Edge and many other ways to reduce the drudgery of making complex selections or masks. Now Photoshop has added a new one: Focus Area.

Focus Area
This new tool is found under the Select menu. It simply selects all focused imagery within an in-focus range that you either specify or let Photoshop do automatically (Auto mode). When the selection is made, you have options to add or delete portions of the selection as well as use the Refine Edge tool.

Though this tool has immense potential in general photography (portrait photography in particular comes to mind), its usefulness in landscape photography may largely depend on the nature of your subjects. The objective of most my landscape photography is to maintain as much sharpness from fore to background as possible. So seldom would I need to select only a focused portion of a traditional landscape scene in Photoshop. However, macro and wildlife photography may greatly benefit from this tool. The reason is you often want to isolate the main subject from any distracting background.

In wildlife photography, you often use a telephoto lens at wide apertures that already blur out the background. But there are times you need to stop down for more depth-of-field and that may increase background clutter. In my case, I don’t do much wildlife photography, but I do occasional macro work and that’s where I often encounter problematic backgrounds. Trying to keep a background that is inconveniently close to the subject sufficiently blurred while keeping the subject in sharp focus can be a challenge at times.

With Focus Area, you can quickly select the sharpest portion of the image, invert the selection (select Inverse under the Select menu), and then run Blur Gallery under the Filter menu. With Blur Gallery, you can now vanquish the background to whatever degree you wish.

Focus Area Example
Below is an example of a cactus flower that competes with a distracting background. This photo is a difficult problem due to the cactus needles, especially those that are slightly out of focus but still part of the main foreground subject. Even if those needles aren’t tact-sharp, I don’t want them caught up in the background blur or else the cactus may look a little “plucked” of its needles.

Original Photo
The background is too busy and competes with the foreground cactus.

To address the problem, I selected Focus Area from the Select menu, which resulted in the screenshot below. To control the selection range, you either adjust the In-Focus Range slider or click the Auto button. In this case, due to the spiny needles, I had to manually adjust the slider for the best results. This accomplished most of the heavy lifting, but I still needed to edit a few small portions of the selection. Initially, I used the Add/Subtract brushes (left of the In-Focus slider) to fix a few of the major offenders (note: to change brush size, use the bracket keys). The Add/Subtract brushes work similar to a Magic Wand in that you don’t need to be exact, just click or roughly paint out the desired area and Focus Area figures the rest out for you.

Screenshot of Focus Area

How perfect the selection should be depends on how much background blur you intend to apply. Obviously, extreme background blurring will reveal selection flaws more, but generally I don’t think you need to be too obsessive about it. In the cactus example, I did improve the selection a bit more by selecting Refine Edge. I enabled Smart Radius and applied about a 6.5 pixel radius and 1 pixel of feathering. Refine Edge will likely be a necessity when shooting wildlife and having to deal with the fine detail of bird feathers or animal fur.

If your image is noisy, then under Advance is an Image Noise slider that may improve the selection. Since I always shoot at low ISOs, I didn’t have any noisy images to test this feature out. Leaving it at Auto should suffice for most of my work, but wildlife shooting often requires high ISOs to freeze subjects with fast shutter speeds. In those cases, you may need to experiment with this adjustment to see if it helps.

After I touched up the selection in Refine Edge, I clicked OK. Back in Photoshop, I inverted the selection and then called up Blur Gallery. Using the Field Blur option, I cranked in about 150 pixels of blur, resulting in the third image below.

Background be Gone!
Results after applying Field Blur