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Old Jan 2, 2019, 7:19 AM   #1
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Default Mirrorless? 'Full Frame'?

First, while mirrorless cameras are smaller and lighter than dSLRs, that doesn't extend to their lenses, which are just as big and heavy as their dSLR counterparts. So the size and weight advantage quickly diminishes as your collection of lenses and accessories grows. Also, the shorter Flange Focal Distance of mirrorless cameras requires their lenses to bend light more in order to project an image over the entire image sensor, so those lenses are more prone to vignetting, chromatic aberration, distortion, and field curvature (soft corners). That is not to say that those flaws can't be overcome, but in order to overcome them, lenses must use more advanced and more expensive designs. Thus, most mirrorless camera manufacturers opt instead to process images in the camera to "compensate" for some of those image flaws. Unfortunately, that processing often simply replaces one image flaw with another, and worse, there is no compensation for the field curvature, and the compensation for distortion actually makes the corners softer. Further, mirrorless cameras are comparatively new, as are their lenses, whereas SLRs and their autofocus lenses have been around for decades, so a new dSLR can use many of the excellent lenses available on the used market at a greatly reduced price. And while dSLR lenses can be adapted to work with mirrorless cameras, use of adapters often introduces other problems in terms of both functionality and image quality.

Second, while 'Full Frame' cameras provide some advantages over APS-C cameras, those advantages are slight and not often realized. 'Full Frame' bodies provide images with slightly better dynamic range and slightly lower image noise, but the larger, more expensive lenses they require often don't provide comparable image quality for what you'd get from an APS-C camera and associated lenses. And while a 'Full Frame' body will allow you to capture images with a slightly smaller Depth of Field, smaller depths of field are more often an encumbrance than a enhancement.

If you absolutely, positively must have the highest quality images, by all means, get a 'Full Frame' dSLR with the highest quality lenses. But be aware: That will come at a significant cost.

So, in general, I'd say you should stick with a less expensive APS-C dSLR.
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Old Jan 25, 2019, 12:17 PM   #2
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Hi, TCav,

Where did you read that the "shorter Flange Focal Distance of mirrorless cameras requires their lenses to bend light more in order to project an image over the entire image sensor, so those lenses are more prone to vignetting, chromatic aberration, distortion, and field curvature (soft corners)." I'd love to read more about this. In our experience, we certainly see these issues in many lenses, mirrorless or dSLR, but Nikon and Canon's new Z and RF lenses are dramatically less prone to these issues, mostly due to how their engineers are able to design the glass for the new mounts. (I'm unable to speak to Sony or Fuji's engineering goals, but even G Master lenses have pretty noticeable aberration). In Canon's case, specifically, their new RF mount lenses are the best in the company's long history (they're also big and pricey).

In terms of mirrorless advantages, you're quite right, the days of "smaller and lighter" mostly only apply to APS-C and M4/3 systems. Still, having shot a full day with the D850 and the Z7/Z6 back to back on various Nikon press trips, I experienced less hand fatigue given the Z bodies smaller size and weight reduction. Also, it's important to note the biggest advantages mirrorless system have over DSLRs is edge-to-edge autofocus points (say goodbye to focus and recomposing), EVFs which represent the camera's current exposure settings, silent shooting modes, in-body image stabilization, and mirrorless burst mode shooting is generally (but not always) faster than similarly priced DSLRs.

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Old Jan 27, 2019, 9:13 PM   #3
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Hi, TCav,

Where did you read that the "shorter Flange Focal Distance of mirrorless cameras requires their lenses to bend light more in order to project an image over the entire image sensor, so those lenses are more prone to vignetting, chromatic aberration, distortion, and field curvature (soft corners)." I'd love to read more about this.


It's actually pretty clear if you know where to look. I've been greatly disappointed that people aren't saying more about this, if they're saying anything at all. Bending light introduces optical aberrations, and the more you bend it, the worse it gets. The short flange focal length means that the exit element must bend light more in order to project an image over the entire image sensor. For 4/3 and APS-C size sensors, the situation isn't too bad, but for 'Full Frame' sensors, the situation is much more difficult. Manufacturers can either make better lenses or correct for the aberrations with in-camera processing. Canon, Nikon and Sony have certainly made some excellent lenses for their 'Full Frame' mirrorless cameras, as can be seen in their retail prices (At least I would like to think that they're turning out some excellent lenses that are able to overcome the problems, since objective test results on Canon's and Nikon's new lenses are hard to come by.), but they've also gone the easy route of in-camera processing, as can be seen in the manuals for Canon's EOS R and Nikon's Z6 & Z7 (a feature, I might add, they never felt necessary in their FF dSLRs.) Sony has hidden the in-camera processing in some of it's lenses by not allowing you to turn it off (We'll have to wait and see how Canon and Nikon handle it.)

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Originally Posted by Palmer View Post
In our experience, we certainly see these issues in many lenses, mirrorless or dSLR, but Nikon and Canon's new Z and RF lenses are dramatically less prone to these issues, mostly due to how their engineers are able to design the glass for the new mounts. (I'm unable to speak to Sony or Fuji's engineering goals, but even G Master lenses have pretty noticeable aberration). In Canon's case, specifically, their new RF mount lenses are the best in the company's long history (they're also big and pricey).
Again, we know that both Canon and Nikon are doing the in-camera processing to "compensate" for at least some of the inherent problems, and we don't know how far they're going to doctor the images that we see. Sony does it automatically to JPEGs, and if you use their image editing application, it happens automatically for RAW images as well. The only way it came to light is when Sony's RAW images were opened in applications that don't automatically "compensate" for failings in their lenses, however expensive they may be. We'll have to wait and see the extent to which Canon and Nikon will go to "compensate" for the failings of their lenses that we just haven't discovered yet, if any.

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In terms of mirrorless advantages, you're quite right, the days of "smaller and lighter" mostly only apply to APS-C and M4/3 systems. Still, having shot a full day with the D850 and the Z7/Z6 back to back on various Nikon press trips, I experienced less hand fatigue given the Z bodies smaller size and weight reduction. Also, it's important to note the biggest advantages mirrorless system have over DSLRs is edge-to-edge autofocus points (say goodbye to focus and recomposing), EVFs which represent the camera's current exposure settings, silent shooting modes, in-body image stabilization, and mirrorless burst mode shooting is generally (but not always) faster than similarly priced DSLRs.
True enough, but I can attest to a failing of EVFs from my experience with Sony, in that, during high-speed burst shooting, instead of actually seeing the composition for the next shot, you're instead looking at the last shot. That makes composing while panning a hit-or-miss situation. For birds-in-flight, auto races and air shows, I very much prefer an optical viewfinder to an EVF. Also, the EVF's generally don't have the resolution appropriate to display compositions with the detail available with optical viewfinders. The data in the following table is old, but it illustrates my point:



The "Magnification" and "Field of View" are straight from the spec sheets of the respective cameras. The "Angle of View (H) (50mm lens)" is the horizontal angle of view of a 50mm lens, focused at infinity, and mounted on the respective bodies. The "AoV x FoV x Mag." is the angle of view of the image in the viewfinder. If the Magnification was 1.00x and the Field of View was 100%, then the "AoV x FoV x Mag." would be the same as "Angle of View (H) (50mm lens)".

Normal visual acuity is 20/20 which is when the human eye is able to resolve detail as small as 1 arc minute, or 1/60 degree. So "Optical Resoution (20/20)" is the number of arc minutes in "AoV x FoV x Mag.". "Opt. Resolution/Degree" is the "Optical Resoution (20/20)" divided by the angle of view, and represents the level of detail the eye can discern in the image in the viewfinder.

The spec sheet for the A3X/A5X gives the electronic viewfinder a resolution of 800x600 (SVGA). So with a horizontal resolution of 800, the electronic viewfinder has a resolution per degree of less that 30. Compared to the resolution of the optical viewfinder in the comparable A5X0, the electronic eye level viewfinder isn't nearly as good as the optical eye level viewfinder. The spec sheet for the A77/A65 gives the electronic viewfinder a resolution of 1024x768 (XGA). The horizontal resolution of 1024 gives that electronic viewfinder a resolution per degree of almost 38. That's a big improvement, but still not up to what is visible through an optical viewfinder.

The 'Full Frame' A900 has a wider angle of view, so the optical resolution is actually slightly less than that of the APS-C A5X0 series. The A99 uses the same XGA electronic viewfinder as the A77/A65, but with the A99's wider angle of view, XGA is woefully inadequate for an average person to be able to discern the same detail that would be clearly visible in an optical viewfinder.
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Old Jan 29, 2019, 4:54 PM   #4
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Maybe slightly off topic but how do cameras with evf's handle prolonged exposure to being cold soaked in -30 ~ -40 temps.
I've had the LCD's go sluggish or turn black from getting too cold but the optical viewfinder and cameras kept on working running off external power sources.
If things keep going the way they are, that'll be less and less of a problem, won't it?
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Old Jan 29, 2019, 9:58 PM   #5
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That's a long long read.
I got through about 1/2 of it but I got the gist of it.
I remember reading about this when the mirrorless e-mount system first came out. I may be mistaken, but I think we discussed this a long time ago.

I do know for a fact that when I used to download raw photo's from my nex-6 the distortion was very noticeable. I would then download similar jpeg's and they would look fine. So yeah, in camera distortion correction. Now days most raw processors have distortion correction and chromatic aberration correction that works well so it's not that big of a deal.

For the size and weight savings, I agree the mirrorless Sony FE lenses are the same size as my a-mount FF lenses, But they do seem to weigh less.

I haven't used the FE system much, so I don't feel I can give an accurate hands on review. But I liked everything about the system except the cost.

I'm still happy with my FF a-mount system and haven't outgrown it yet and don't think I ever will. As long as I can keep the a-mount working I don't feel the need to switch to the FE mount.

Now, with that being said I do have a Sony A6000 travel kit. I really like the A6000 and 18-200 LE combo. It's small, light, reasonably priced and produces excellent images.

Along with the 50mm f/1.8, Rokinon fisheye, HVL 20 and 42 flash with an adapter and a bag just big enough to hold it all. I find it the perfect travel kit for my needs.

So, to summarize, APS-C e-mount I'm in. FF e-mount? Nope.

Mirrorless does have its place and seems to be the way of the future for still photography.

Not sure what your talking about regarding the viewfinders.
I never get tired of the a900 viewfinder. I find it the best optical viewfinder I've ever used.
The e-mount electronic viewfinder (EVF) took some getting used to but it doesn't take long.

I like the EVFs ability to see it before you shoot it.

I don't have a preference for either viewfinder they're just different and you've got to get used to each of them.
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Old Jan 30, 2019, 8:48 AM   #6
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I do know for a fact that when I used to download raw photo's from my nex-6 the distortion was very noticeable. I would then download similar jpeg's and they would look fine. So yeah, in camera distortion correction. Now days most raw processors have distortion correction and chromatic aberration correction that works well so it's not that big of a deal.
But while distortion compensation works to make straight lines straighter, the process plays with the pixels in order to achieve its result, which makes the corners softer. And given the increased field curvature that is a natural consequence of having such a short flange focal distance, the corners were pretty soft to start with, so while distortion compensation may correct for one flaw, it exacerbates another for which there is no compensation . On smaller sensors like 4/3 or APS-C, it may not be so important, but for 'Full Frame' sensors it's substantial.

I do concede that CA compensation works well, as has always been the case, either in-camera or in post. I've had lots of experience with the CA I get with my Nikon 85/1.8 in high contrast images, and Nikon's ViewNX 2 has worked well for me in that regard. But distortion compensation and shading compensation only replace one image flaw with another. And there is no compensation for field curvature (soft corners) that the process of distortion compensation makes worse.
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Old Feb 1, 2019, 12:04 AM   #7
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Although my experience with e-mount is mostly with the aps-c system. The distortion it exhibited was bad. Most would probably not even notice the distortion while looking at the photo's. After comparing the raw to the jpegs I always noticed it. Wish I'd never compared them.

I'm sure FE mount is worse. And while compensation messes with the pixels the fact is if I were using an FE-mount system, after the distortion compensation, chromatic aberration correction, I am going to mess with the pixels even more with adjustments.

Just so it looks good in the end.

Recently switched to a new raw processor that has distortion correction, and I'm noticing even some of my a-mount lenses have some distortion. After using some of these lenses for many years it's never been a problem.

Honestly if I were using FF e-mount I wouldn't worry about it.

I am just shooting to have fun and those field curvature issue's are just something I can work with, work around or even better, use them to my advantage in certain sitautions.

I've definitely made some not-so-thin females look much thinner with distortion.

You just have to master your tools.
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Old Feb 1, 2019, 5:29 AM   #8
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Recently switched to a new raw processor that has distortion correction, and I'm noticing even some of my a-mount lenses have some distortion. After using some of these lenses for many years it's never been a problem.
Nobody said that A-Mount lenses were perfect, but Sony never opted to include compensation for them until the need arose for their E-Mount lenses and bodies.

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I am just shooting to have fun and those field curvature issue's are just something I can work with, work around or even better, use them to my advantage in certain sitautions.

I've definitely made some not-so-thin females look much thinner with distortion.
(ROFL)

All things being equal, I'd prefer a system of good lenses to a system that compensated for bad ones.
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Old Feb 18, 2019, 8:26 PM   #9
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this thread is awesome
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Old Feb 21, 2019, 3:12 AM   #10
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Great discussion so far but I like to add some comment regarding the EVFs in mirrorless. I shoot with both and have no preference either way but let's go through them:

1. Unlike what you see in an optical viewfinder which in real-time, what you see in an EVF has already happened... Think about it this way, an action image you try to catch in an EVF has to be captured first by the sensor and regardless of how fast this computer is in the camera, this image has to be digitized then processed.... AND then re-displayed to the electronic viewfinder. None of theses serial events occur with an optical viewfinder
-> This is why some of the newer cameras with EVF capture a scene before the shutter is pressed, because once you see it, this event has already happened before you can press the shutter because of the electronic processing involved!

2. I shoot in the studio with mirrorless too and it required a different technique. The EVF has both its own advantages (and disavantages) in a dark studio with strobes and if you have not been in one be prepared for a few surprises when the camera is on manual - LOL
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