The Resolution Question

[Rob Gardner]

Your "reality" is predicated on the inability to achieve accurate focus even in the easiest and most controlled circumstances. Live view makes it so easy (especially at f/11), that it should not take any photographer more than a few seconds. That's separate from autofocus or miscalibration, of course.
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You are very quick to presume my inability to take a picture in focus. Over the past 20 years, I think I've managed that once or twice. And the fact that the 1D shot is in perfect focus should alleviate any doubts you may have about this user. You are drowning in your arrogance, and your condescension is no lifeline. I joined this forum to share images, experiences, and have fun. It's people like you who ruin it for everyone.


As I stated before, I chose my test target for a reason - multiple flat surfaces at multiple depths - to make it easy to discern results. SOMETHING in that image should be sharp and in proper focus, but it is not.


Feel free to argue your charts and resolution formulas to your heart's content. I hope it serves you well. Some of us actually have to make a living using these little black boxes, and I've clearly wasted enough time on this topic. For those I have somehow offended with this post, my apologies.

[Sean Setters]

Alright guys, settle down. Somewhere in here we strolled past the constructive discussion phase in relation to the topic. I think you both (Rob and Daniel) have made good points, so let's try to keep the conversation going in a constructive manner.


Personally, I've noticed that shots with my 50D are sometimes soft when I think they ought not to be. Did I miss focus? Possibly. I know that my 70-200mm f/2.8 L IS worked best after a microfocus adjustment of +15. It's possible that the 50D's "zero" focus is a bit off by nature; or maybe its anti-aliasing filter is set relatively strong when rolling off the factory line. However, the images do take sharpening in DPP fairly well. Rob, you might want to try doing another microfocus adjustment to get the most out of your lens/body combination. [EDITED] If you've maxed that out, and you're still seeing a substantial softness, then anyone else's opinion on the issue doesn't really matter--you should send the lens and body to Canon for adjustment like Colin says below. But when you ask a question, be prepared to get a variety of answers. Take from those answers what you will and don't take it personal when someone disagrees with the way you're rationalizing your own position on the matter.


I've also learned that from the technical side of things, Daniel is usually spot on and can provide evidence to back his position. However, Daniel, you could be a bit less assertive [aggressive] in arguing your stance.


At the end of the day, we're a community that should strive to respect one another whether we agree with them or not. :-)

[Chuck Lee]

I was not responding to you or anyone else when I made the test chart comment. In fact, I wrote that post sitting in a cigar bar with no internet access, not having read your post. Why you would take it to refer to you personally is beyond me. I apologize for offending your sensitivities.

Apologies accepted. I'm not sure the nature of that particular post from the cigar bar. Neither am I trying to offend. That's not what we do here.


In your profile you say "Looking for shooting buddies and constructive criticism". Now, I'm not in NewYork, but if your're ever down in Williamsburg, VA, I'd love to go out and shoot somephotos. Just let me know. Secondly, You posted a topic illustrating that the resolution (15MP) of the 50D is inferior to the resolution of the 1DMkII (8.2MP) which in my humble opinion makes no freak'n sense.


Your problem is with focus or diffraction yet you continue personal attacks rather than facing the facts as presented. Yes, there are sharp portions of leaves in the 50Dimages you posted. The flat leaf to the back right is much sharper in the 50D than the MkII shot. The 50D is obviously "BACK FOCUSING". You have said nothing about the Diopter adjustment on the viewfinder. You also have not mentioned 10X zoom in live view. So, what are we to think. Every time someone says something it's taken as a personal attack on your 20 yrs of photographic knowledge. You said that the micro adjustment was at +20 and needed more. Obviously, to the objective observer you either haven't a clue what your're doing or the AF on your50D is a mess. What would you think reading that?


I'm sorry your having a hard time with the 50D. Sean Setters obviously loves his. (ask him, he's a forumfriendof yours) I, as well as others have tried to suggest things you may be over looking to somehow help you resolve this issue that we can't ourselves replicate. That's know as "constructive criticism" which I believe you are on this forum looking for. I am a member of this forum because I found TDP first and studied much of the information that Bryan C makes available here. It is a treasure trove of knowledge. i.e. f11 sucks on a 50D and if you continue to dispute that then you are hardly fulfilling the mission statement written in your profile. So suck it up and try f6.3 and maybe things will look better in the morning.


So, In my opinion, if you detest the current 50D that you own, return it, or sell it, or throw it in the Hudson River and get on with the more important matter of making great images. Please, when posting, ask questions that you are sincerely looking for answers on rather than using it for a place to vent about your unhappiness with a recent equipment purchase. Except for Conway Yen, I don't think you'll find too many others agreeing with your post or conclusions.


And yes, we've all wasted toomuch time on this topic. The big thing you miss is the effect your opinion has on those looking for answers. When they come across your post do they run forNitax because of your inaccurate tests and conclusions or do they find accurate, intelligent answers and insights that help them wisely purchase and use Canon photographic equipment. I don't know if you care. I honestly don't think you do. Forums are more than a whiteboard for slander. They're a great source of education and knowledge.


Thanks Sean, I just read your post as was finishing up. Community......that's the deal. Sorry if I'm being to "assertive" here.

[Daniel Browning]

You are very quick to presume my inability to take a picture in focus.

I'm sorry that I did not make myself clear. I did not mean that you do not have the ability to ever take a picture in focus. What I meant was that your conclusion ("1D2 has more resolution in reality") is based on an invalid comparison, because you were not able to get the comparison photos in focus. The reason I said that is because of two facts:

• The 50D photo is clearly
  and obviously out of focus compared to the 1D2 shot. The two photos do
  not have the same plane of focus.
  
• You said you spent over an hour and more than twenty shots to get one in focus:

On a tripod, in
controlled lighting, from a motionless inanimate object, I EXPECT TO
GET AN ACCURATE SHOT. Otherwise I may as well give up the business. I
tried to focus 20 different shots, both manually and with AF. The shot
shown is the best manual focus shot I could take. I have 20/20
uncorrected vision. I spent an hour screwing with the AF
Microadjustment.

What I meant to convey is that the reason for the difference in your comparison (and incorrect conclusion) is due to the missed focus, and since any photographer with liveview can achieve the correct focus in the given circumstances, the problem does not lie with the 50D.

And the fact that the 1D shot is in perfect focus should alleviate any doubts you may have about this user.

I disagree. Many of the 1D features make it easier for the user to achieve accurate focus: a better autofocus system, higher AF accuracy, stricter calibration standards, and lower resolution. The 50D, in comparison, is generally more difficult to achieve accurate autofocus (microadjustment excepted).

[Colin]

I know that when I sent my 5D in to have the 135 f/2 matched for focus, the results that came back were WAY better.


If the 50D won't micro adjust enough, it (and the lenses you're going to be using) simply need to go back to the factory to get in tune.


Rob, I really do understand your frustration. I was ready to throw my 135mm under a car, or better yet, go beat the Canon Technical support guy who informed me that my lens wasn't back focusing, I just needed to stop down.


That still pisses me off.

[Rob Gardner]

What I meant to convey is that the reason for the difference in your comparison (and incorrect conclusion) is due to the missed focus, and since any photographer with liveview can achieve the correct focus in the given circumstances, the problem does not lie with the 50D.

You are assuming that the camera is functioning perfectly. Is there any chance in your world that it could be the machine, and not the user? See below...

And the fact that the 1D shot is in perfect focus should alleviate any doubts you may have about this user.

I disagree. Many of the 1D features make it easier for the user to achieve accurate focus: a better autofocus system, higher AF accuracy, stricter calibration standards, and lower resolution. The 50D, in comparison, is generally more difficult to achieve accurate autofocus (microadjustment excepted).
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Did you bother to read where I stated that I used MANUAL focus to get that shot, as the AF was having too much difficulty?? And, for the record, I have AF set to the AF-On button on all my bodies, so there's no chance of the AF overriding my manual adjustments as I depressed the shutter. And I used a remote shutter release to eliminate any user-generated camera movement.


It amazes me how someone can so vehemently claim that it HAS to be user error, because the camera certainly cannot be defective, malfunction or have difficulty producing an accurate image in any way. The FACTS are this - 1) I was visually able to produce (and reproduce EVERY time) an in-focus image with the 1D by using my little analog eye to look through the pretty little picture hole in the top of the camera, and twisting the rubber knob around the lens. 2) Despite trying every method available (AF, manual, LiveView) I could not get a clean image given my parameters. 3) I later tested a Canon 10D in the same conditions, and produced a sharp image.


So I just went back this morning to change parameters and reshoot, taking the advice of opening up to f/5.6. I took shots using manual and LiveView, trying to leave AF out of the equation. This produced dramatically different results. Using the same methods as before, my image quality was significantly better. So I went back to f/11 to see if I could reproduce the same issues as before, and sure enough, I got the same crap. The scientific method of reproducible results points to a camera issue, not a user issue, in the real world - not on a spec chart.


At f/5.6, this 50D produces a very usable image. However, in my world, I do need a camera that produces acceptable images from f/1.4-f/22 (lens-dependent, of course). If my cutoff point is f/7.6 or so (regardless of lens), that severely limits this camera's usefulness to me. I am going to bring the body in to Canon to have them take a look and make sure there is nothing wrong with this particular unit - and get some use out of my CPS membership.


This post has taught me a very valuable lesson. There are those on this board who are here to become better photographers, and those who like to talk about specs and data. There are those who post frequently about tech and love to tell others how wrong, misguided, or ignorant they are about physics, science, and technology - yet little of it is actually about why we are here (835 posts to this forum, only one was about an actual picture taken by the author of said posts). I clearly do not belong here.

[Rob Gardner]

Secondly, You posted a topic illustrating that the resolution (15MP) of the 50D is inferior to the resolution of the 1DMkII (8.2MP) which in my humble opinion makes no freak'n sense.

My original post made no such statement about resolution - it was about image quality - two different points. The post was about the idea in my crazy head that my 1D Mk II was out of date and inferior to today's technology in the mid-range, that I could replace the 1D Mk II with a 50D for the same money and it would be an "upgrade". It illustrated the difficulty I was having with generating a clean image from the 50D that worked as well as the older 1D. I was not saying that the 50D was an inferior camera, but merely that the 50D did not provide the upgrade I was (perhaps inaccurately) expecting, given its superior specs in certain key areas.

Your problem is with focus or diffraction yet you continue personal attacks rather than facing the facts as presented.

I never "attacked" anyone. You might want to go re-read your original and unsolicited responses to myself, and Mr. Browning's responses to Conway Yen and myself first, before you level such accusations. And yes, I stand by my comment that it is arrogant and condescending of Mr. Browning to tell me that any idiot can perfectly focus a 50D with LiveView in a matter of seconds. In theory this is true. It looked good on the screen, but the file produced different results.

You said that the micro adjustment was at +20 and needed more. Obviously, to the objective observer you either haven't a clue what your're doing or the AF on your50D is a mess. What would you think reading that?

I started AF Microadjustment by taking 5 shots, starting from -20 to -10 to 0 to +10 and +20. The shots progressively got better from -20 to +20 - it was as far as I could go and there was no "sweet spot" in between. I am limited by the software parameters - what else can anyone else do? How do I "not have a clue as to what I am doing"? Once again, you imply that I'm an idiot. Thank you for proving my point about personal attacks.

I, as well as others have tried to suggest things you may be over looking to somehow help you resolve this issue that we can't ourselves replicate.

Have you tried replicating the issue? Obviously not. So don't bother us with specious comments like that.

That's know as "constructive criticism" which I believe you are on this forum looking for....Please, when posting, ask questions that you are sincerely looking for answers on rather than using it for a place to vent about your unhappiness with a recent equipment purchase.

My original post did not ask questions. I sought neither "constructive criticism" nor was it "venting unhappiness about a recent purchase". It was you who provided answers to questions I did not ask. It was sharing my own observations in my unique situation. I never made a claim that "all 50Ds suck" or some such nonsense. I was not reviewing the camera for general consumption...I had a unique situation with a unique perspective. I shared it with the community, which as you have pointed out was a very big mistake. As to the effect my opinions have on this board, you have made it clear to me that individual observations on this "whiteboard for slander" are not welcomed. Not to worry - I got the message.

[Daniel Browning]

You are assuming that the camera is functioning perfectly. Is there any chance in your world that it could be the machine, and not the user? See below...

No, not in this case. It's very obvious from the picture itself that you simply missed focus. If you were testing the autofocus performance, then it would make sense to blame the machine. But in this circumstance you were not.

Did you bother to read where I stated that I used MANUAL focus to get that shot, as the AF was having too much difficulty??

I thought that only applied to the 50D. In any case, the 1D2 has several advantages over the 50D for manual focus as well, such as a larger, brighter viewfinder and thinner DOF (for the same framing and f-number, as in your comparison). (I always replace the standard viewfinder screen with a precision one as well. If they differ in that way it would be another advantage.)

So I just went back this morning to change parameters and reshoot, taking the advice of opening up to f/5.6. I took shots using manual and LiveView, trying to leave AF out of the equation. This produced dramatically different results. Using the same methods as before, my image quality was significantly better. So I went back to f/11 to see if I could reproduce the same issues as before, and sure enough, I got the same crap.

The issue of f-number is separate from and in addition to missed focus. There's not much sense in comparing the difference in contrast caused by diffraction when there is a much, much larger difference in contrast caused by missed focus. In fact, I would think that a correctly focused 50D would still yield greater resolution in the face of more diffraction. The reason it has more diffraction, of course, is only because you shot the 50D at a deeper DOF than the 1D2. The 50D would require f/8 to get the same optical DOF as f/11 on the 1D2.


There is a third issue as well: the MTF of the lens. Since the 1D2 uses a different image circle, the spatial frequency of any given print size is 1.3X lower than the 50D, so the contrast of the lens will be higher at any f-number that is not dominated by diffraction.

The scientific method of reproducible results points to a camera issue, not a user issue, in the real world - not on a spec chart.

You still have not posted any images where both are focused at the same distance, and/or the same depth of field. If you were to do that, it would prove the opposite of your first post: the 50D has far more resolution than the 1D2.

At f/5.6, this 50D produces a very usable image. However, in my world, I do need a camera that produces acceptable images from f/1.4-f/22 (lens-dependent, of course).

That's nonsensical. At f/22, the 50D has a depth of field that is far deeper than the 1D2 at f/22. You only need f/17 or so on the 50D to get the same DOF as f/22 on the 1D2. The only possible problem I can imagine is that the 50D is too sensitive, you can't get your shutter speed slow enough, and you dislike using ND. If you fall into that rare circumstance, then I agree with your problem, but it's just a natural consequence of sensor size and has nothing to do with the specific implementation of the 50D, and applies equally to all APS-C for a given level of technology.

If my cutoff point is f/7.6 or so (regardless of lens), that severely limits this camera's usefulness to me.

That is only the cutoff point to get the maximum possible return from the additional resolution of the 50D over previous cameras. You can still use it at any given DOF and get more resolution than previous cameras. You only have to use f/7.6 if you want the maximum possible return (rather than just a modest improvement).

835 posts to this forum, only one was about an actual picture taken by the author of said posts

So what? Posting pictures is not a requirement to be a part of this forum. I share my prints with people in real life and I get all the feedback I could want, so I have no need to post photos online for discussion. The reason I come here is for discussion of the more advanced and technical aspects of photography which I do not find in my real life circle of acquaintances.

[ShutterbugJohan]

No offense anyone, but a simple way to end this debate would be to put a lens with tripod collar on a tripod, MF with the 1D II, then swap to the 50D without adjusting the lens focus. There should be no room debate then...


$0.02

[Rob Gardner]

...and that's what I did. 70-200 f/2.8 L with tripod collar, Manual focus, remote shutter release, 200mm at f/11, ISO 100.