dcstep

<p>Marcus said:</p> <blockquote> <p>However, it is not a relevant distinction, because this lens is an EF (L) lens, and can therefore be mounted on any EOS camera ever made... awhile back, those included film cameras... </p> </blockquote> <p>Great, now show me the test results on film. Thank you for illustrating my point!</p> <blockquote> <p>While I agree, it is not mere 'gimmickry', it<em> is</em> a software modification to an image file (aka image editing). It is the same as NR in that respect, and yes, while each sensor will have it's own 'opinion' about what it 'sees', the broad characteristics of the image will be exactly the same. ie. I can mount one to my 5D2s, then my old 5D, then a 5D3 or a 1Ds, and <em>all the images will share broadly similar distortions in the OOC Raws (or JPGs of course!)</em>. This is why we test lenses... to see how bad or good they are. -- In fact, if I shoot with it on my Elan, I would bet a fair amount of money that you would see very nearly exactly the <em>same distortion apparent in the image</em>.</p> </blockquote> <p>When testing, are we only looking at "broad characteristics" or are we interested in detail differences? If you're only interested in "broad characteristics" then you will not care about optimized performance, but some of us want to see optimized performance.</p> <blockquote> <p>I don't understand why some would argue that a lens's characteristics be defined by the results <em>after</em> image editing (in this case distortion correction). We don't typically define a sensor's noise characteristics after we've run NR on the image, specifically because every piece of software does it a bit differently. Same goes for this... and don't forget, while those who would use this lens on film are indeed few and far between, those who shoot JPGs are NOT.. Those who shoot JPGs may or may not ever use an image editor capable of distortion correction (or may not bother). Just because some do, doesn't mean ALL do. -- Which is exactly why understanding the UN-edited optical characteristics of a lens are so important.</p> </blockquote> <p>We're talking about lens testing, not body testing. Noise and in-camera JPGs are a representation of the body's ability to interpret the image, filtered and then captured on the sensor. When testing a body, we'll want to see in-camera JPGs to get an idea of color interpretation, avoidance of purple fringing, moire handling, dynamic range, noise production, etc., but that's only there for those that don't use external Raw conversion software. DPReview, for instance, will show Raw conversion with the manufacturer's external software and, sometimes, one or two other Raw conversion programs. I ignore the JPGs samples, but really get into the Raw conversion sample images. Many will only look at the JPG samples.</p> <p>There's really no such thing as an un-edited digital image. Even the in-camera JPGs is based on the tastes of a Japanese committee. The in-camera processor applies pre-determined RGB, Contrast and, in some cases, Digital Lens Optimization, among other things. There is no "Raw image", it's a Raw data file.</p>

<p>Wouter said:</p> <blockquote> <p>Here we disagree; it is not gimmickry, but it most certainly is not necessary. I shoot both digital and film, with the same lenses - how come on digital distortion correction would be necessary, while it would be perfectly fine to leave it as-is on film? Lens corrections are nice-to-have, but not the end-all-and-be-all of imaging. Let's not act like it makes the critical difference.</p> </blockquote> <p>Exactly my point, there's no digital distortion on film, but there most likely is with digital capture. The degree of digital distortion may not be enough to worry with, but that's dependent on the body/lens combination. Zoom, lenses, particularly those including wide-angle, will have variable chromatic aberration, vignetting, geometric distortion, etc. which is more likely to be course enough at certain aperture/focal length combinations to warrant correction. Some digital bodies will respond to lens imperfections by adding purple fringing, moire, etc. that further aggravates the lens' imperfections.</p> <blockquote> <p>There is no such thing as a <em>digital lens</em>. Using it on film doesn't make it more native than it is on digital. Lenses are lenses, optical devices; they transmit light, and that's it. Some lenses have coatings optimised for the reflection of a sensor (instead of film), but that's as digital as lenses get. A sensor can render some optical defects more noticeable than film does, but the lens still does the very same thing - it is unaware of the recording medium that sits behind it (and yes, I use the same lenses on my digital bodies as I use on my film bodies).</p> </blockquote> <p>You said it yourself, "Some lenses have coatings optimized for the reflection of a sensor." Until digital capture came along, we didn't see these lenses. I believe that they're rightfully called "digital lenses", because they're optimized for digital capture. Still, with the right mount, you can put them on a film camera.</p> <blockquote> <p>It is nonsense to try to define what is the most accurate representation of a scene. Anything in camera is just a bunch of data that needs interpretation (which raw processor is the accurate, which lens profile is most correct etc. etc.?). There are various ways, which all have their validity (with different advantages and disadvantages). Acting like there is one single correct way is underestimating seriously the complexity of the situation.</p> </blockquote> <p>I believe that test patterns, models and certain static displays do allow a certain level of repeatable performance where the captured image can indeed be compared to reality and judged for accuracy. Despite their limitation, I find the test images at http://www.the-digital-picture.com/Reviews/Comparison-Tools.aspx useful. I also like the DPReview sample images using their little mock scenarios. Still, particularly with zooms, I think it'd be very useful to see those same images after applying the manufacturer's DLO correction in Raw conversion.</p>

<p><strong>BUNNY BATTLE!</strong><br> <strong> </strong></p> <p><a title="First Strike by David Stephens, on Flickr" href=" src="https://farm3.staticflickr.com/2897/14608280353_1f23913a61_c.jpg" alt="First Strike" width="800" height="534" /></a></p>

<p>So Robin, you seem to say that the in-camera Raw file is accurate representation of what the lens saw? If so, we disagree.</p>

<p>Dan said:</p> <blockquote> <p>The point you are trying to make here is unclear to me.</p> </blockquote> <p>I was talking about the digital capture process introducing errors and the Raw conversion process removing errors. Unfortunately, Raw conversion done poorly also introduces errors. </p>

<p>Marcus, none of us are going to shoot film just because it's the only way to know the actual performance of our lenses. However, if it's possible, it'd be nice to see digital lenses tested on film bodies so that we could see what the native lens actually can do.</p> <p>Take one Canon lens and three Canon bodies and take the same test image with each body. The three resulting images will not be the same when you examine the OOC RAWS in detail. Canon, DxO and, I assume Lightroom, take test images with lenses at every aperture and every focal length and every body that they support. The corrections a slightly different for every body. </p> <p>This is not "gimmickry" but a necessary part of the digital capture process. You can pretend to test one part of a system by ignoring the two other parts, but then you're going to try to reach conclusions with incomplete data. </p>

<p>Remember, you can't "maximize the result in the field" if your shooting digital. The capture process introduces errors and the Raw conversion process can correct errors and/or add errors. Luckily, applying DLO correction doesn't add to Raw conversion processing time. You either turn it on and leave it on, or turn it off. The processing is automatic and requires no time.</p> <p>When we shot Kodachrome, Ecktachrome, Fujichrome, etc., we tried to get exposure perfect. If you didn't "maximize the result" in the camera, there wasn't much to save or do. Now, when conditions allow, many (most?) of us "expose to the right", over exposing the image so that the uncorrected image looks washed out. This practices maximizes the color and brightness information in the Raw file. In Raw conversion, we then "normalize" the exposure and contrast to get it to the image that was in our mind's eye. It's a totally different world.</p>

<p>Dan said:</p> <blockquote> <p>While I see the objective value in understand the underlying uncorrected lens capabilities, I've often thought that rather than trying to isolate everything that a more interesting and useful test would be to put two pieces of gear into the hands of a very skillful photographer (or photographers) and see what the end result would be when everything is optimized in precisely the way that skillful photographers will optimize them.</p> </blockquote> <p>I'm of this mind and I think Wouter is also; however, I've never really seen this happen.</p> <p> I also avail myself of the luxury of borrowing a lens and/or body from Canon Professional Services to see how the images look on my computer. People that don't belong to CPS can rent a lens for a short period, or rent two when you're narrowed down that far.</p>

<p>Understood Wouter.</p> <p>I agree that the proof is in the shooting. For zoom lenses, like the OP 15-35mm, shot at a wide variety of apertures and focal lengths, I can't imagine a user preferring the results uncorrected vs. using a competent DLO program.</p> <p>The expense of high quality lenses is indeed quite high, as you state, so I like to maximize my chances for a sharp image by engaging DLO. BTW, other than fisheye images that I often de-fish partially, I've never backed off the DLO to get a better result. That includes a number of 50" prints.</p>

<p>Patrick S said:</p> <blockquote> <p>David Stephens - you should write the State of Iowa to see if they might be interested in that Goldfinch shot. It's our state bird. Simply spectacular.</p> </blockquote> <p>Thank you Patrick. Goldfinch are one of my favorite subjects. In Iowa, do they tear up the thistle in late July and August? That's my favorite times to shoot them, trying to get the thistle flying at the goldfinch with seeds on its beak. </p> <p>I'll do a little follow-up on your suggestion.</p>

<p ><a name="00cgYM"></a><a href="/photodb/user?user_id=5189561">Wouter Willemse</a> <a href="/member-status-icons">said:</a></p> <blockquote> <p>Still, those lens correction technologies - which are not part of the lens - should you really be testing a lens with those enabled to see what the lens is capable of? It's seriously a question, but obviously I have my doubts.<br /> The capabilities of the camera and software should be excluded or normalised as much as possible when testing a lens. If you want to test a total system with the lens as an integral part of a chain, it's a different thing. But if the lens has chromatic aberrations, distortion or whatever, lens testing should reveal it - not hide with software optimisations. Or am I completely missing a point now?</p> </blockquote> <p>Good point Wouter, but I've thought about it a lot also and come to the opposite conclusion, because we can't escape the fact that the body digitally alters the image during capture. Still, I respect your position. If we could test a lens without using a digital body, then I'd agree with you. Unfortunately, the lens is part of a digital system; body/lens/software.</p> <p>Of course, I realize that testing labs face a huge problem because we all use so many software. I suppose that if it were a Canon lens on a Canon body, then they could show the results from Digital Photo Professional. That would be meaningful and as the manufacturer intended. I think that all the major manufacturers have their own Raw conversion software, but I don't know if all have DLO, as Canon does.</p> <p>Unfortunately, DPP does not offer DLO for non-Canon lenses, like Sigma and Tamron. For those, the tester could use DXO, LR or another Raw converter, but then the test becomes as much of a test of the software as it is a camera/lens combination. That's a big ole can of worms, BUT I'd still like to see some reviewers try to address it. They're really ignored it for the last few years. I haven't found an in-depth discussion of DLO in any of the major photography magazines.</p> <p>For us regular users, I say do your comparisons with and without DLO engaged and decide for yourself. In my case, back in 2009, I was ready to send my EF 24-105mm f/4L IS back to Canon of a look see since I was having problems with softness and CA. When I started using DxO Optics Pro, my problems went away. The 24-105mm is now one of my go-to lenses.</p>

<p>Excellent post and examples Dan.</p> <p>DOL have been improving steadily since Dan's original post.</p> <p>It's easy enough to try for youself. DLO comes as part of DPP, which ships with any Canon DSLR.</p>

<p ><a name="00cgSi"></a><a href="/photodb/user?user_id=23754">Robin Smith</a> said:</p> <blockquote> <p>Distortion correction will be destructive at the pixel level as one can't stretch, eliminate, or duplicate pixels without losing detail: if one worries about such things.</p> </blockquote> <p>This line of thinking assumes that the filtering and digital capture process doesn't do any damage, as if we were shooting on film. Use the same lens on three different body models from the same manufacturer and you'll get three different results. That's what we're talking about correcting.</p>

<a href=" title="Deep Woods Heron by David Stephens, on Flickr"><img src="https://farm3.staticflickr.com/2912/14093598920_a4899cbeb7_c.jp g" width="534" height="800" alt="Deep Woods Heron"></a>

<a href=" title="Stormy by David Stephens, on Flickr"><img src="https://farm3.staticflickr.com/2437/3680183640_e270549826_z.jpg" width="640" height="433" alt="Stormy"></a>

<p>You should consider looking at results after Raw conversion with Digital Photo Professional and applying Digital Lens Optimization in Raw conversion. If you're using these lenses and not applying DLO, you're not getting the most out of your lenses.</p> <p>People still test lenses as if they're still using film. With digital sensors, you have filtering and correction during the capture process, such that the resulting image doesn't not necessarily represent the actual ability of the lens. Applying DLO makes correction at every focal length and every aperture to correct for distortions in the lens and introduced by the camera during the capture process.</p>

<p><strong>Blooming Cactus</strong></p> <p>Canon 5D MkIII, EF 15mm f/2.8 fisheye, Av Mode,ISO 400, +1EV, f/16, resulting in 1/80-sec., hand held, with Raw conversion and de-fishing, in DxO Optics Pro 9.5:</p> <p><a title="Blooming Cactus by David Stephens, on Flickr" href=" src="https://farm6.staticflickr.com/5118/14542450853_8556a1d072_c.jpg" alt="Blooming Cactus" width="800" height="800" /></a></p>

<p><strong>Goldfinch Poses</strong></p> <p>Canon 5D MkIII, EF 500mm f/4L IS, EF 2.0x TC-III, Av Mode, ISO 800, +1EV, f/8, resulting in 1/1250-sec., with Raw conversion in DxO Optics Pro 9.5:</p> <p><a title="Singing Goldfinch by David Stephens, on Flickr" href=" src="https://farm3.staticflickr.com/2905/14526625392_2ebf42e17f_c.jpg" alt="Singing Goldfinch" width="800" height="800" /></a></p>

<p><strong>Yummy Prairie Grass</strong><br> <strong> </strong><br> Canon 7D, EF 70-200mm f/4L IS, EF 1.4x TC-III, at 169mm, Av Mode, ISO 400, +1EV, f/6.3, resulting in 1/160-sec., hand held, with Raw conversion in DxO Optics Pro 9.5</p> <p><a title="Yummy prairie grass by David Stephens, on Flickr" href=" src="https://farm6.staticflickr.com/5567/14335700240_fe77217ae1_c.jpg" alt="Yummy prairie grass" width="800" height="800" /></a></p>

<p>Milkweed in the front yard! Do you have some thistle also? ;-)</p> <p>Lots of flowers classified as "noxious weeds" actually look pretty good to me. I guess they're called noxious weeds because they can take over, if you're not very careful and very aggressive in their control.</p>

<p>Generally you'll use Aperture Priority or Shutter Priority when you want the camera to react to changing light conditions. In the situation that you describe (portrait shooting), then you may prefer Manual mode OR you can use Exposure Lock to lock the exposure and recompose. Look in your manual to see which button to push to lock exposure when in any Auto Exposure Mode.</p>

<p><strong>Singing Goldfinch</strong><br /> <br /> Canon 5D MkIII, EF 500mm f/4L IS, EF 2.0x TC-III, Av Mode, ISO 800, +1EV, f/8, resulting in 1/1250-sec., hand held, with Raw conversion in DxO Optics Pro 9.5</p> <p><a title="Singing Goldfinch by David Stephens, on Flickr" href=" src="https://farm3.staticflickr.com/2905/14526625392_2ebf42e17f_c.jpg" alt="Singing Goldfinch" width="800" height="800" /></a></p>

<p>Trevor asked:</p> <blockquote> <p>... David your finch picture is amazing. Bright, crisp, vibrant & beautiful. Just out of curiosity, lets say you own a 5D III already & you had to choose a cropped censored Canon body today which one would it be? I chose the 7D mostly because it closely matched the 5D III layout\design so when flip flopping equipment I'm not fumbling around trying to remember where all the buttons are. I heard the new 7D II is coming soon but not the same design/layout if I remember right.</p> </blockquote> <p>Thanks Trevor.</p> <p>I owned the 5D MkII first, then the 7D and finally the 5D MkIII, purchasing each soon after they became available. The 7D was my bird and wildlife body until the 5D3 came along, with AF so superior that it was no contest. I make up for the lack of pixel-density by using TCs most of the time, so my 500mm is usually operating at 700mm or 1000mm.</p> <p>I still own my 7D, but keep it strung around my neck as my second camera with my 70-200mm f/4L IS mounted, usually with the 1.4x TC-III also attached.</p> <p>If I already owned a 5D3 and thought that I needed a crop-sensor body, considering my need for fast response, I'd still get the 7D, despite it's old sensor and relatively poor high-ISO performance and the inconsistency of its AF system in AI Servo mode. However, I'd probably wait on the 7D MkII, because the 5D3 is pretty darn good. Keep in mind, I have a 500/f4, so I'm not feeling too focal length limited.</p> <p>All the above relates to shooting birds, wildlife and action. For street shooting, portraits, travel, etc., there are lots of other options available. For my general use friends that want a really great DSLR, I recommend the 70D or the 6D.</p>

<p>Don't forget about the EF 2.0x TC-III. I use mine with my EF 500mm f/4L IS almost 90% of the time. The IQ is excellent and with either of the f/2.8 lenses you're consider, it'll work on any body.</p> <p>For birds and wildlife, I'd go with the 5D MkIII over the 7D for its much more consistent and accurate AF system, ability to AF at f/8 and superior high-ISO performance. I own both, but the 7D sensor is five-years and three-generations old.</p> <p>I shot this goldfinch yesterday with my 5D3/500mm combination with the 2.0x TC-III added. Hand held. More pixels on the subject is always good:</p> <p><a title="Singing Goldfinch by dcstep, on Flickr" href=" src="https://farm3.staticflickr.com/2905/14526625392_2ebf42e17f_c.jpg" alt="Singing Goldfinch" width="800" height="800" /></a></p>

<p>Yes, you just need a valid serial number for one of the supported models.</p>