[wim]

.....

Pretend I know nothing about cameras.  Is it really that easy to change focus screens on the 6D, and the secret is to stick with Canon made screens?  That is VERY valuable information, and all of us Canon shooters are adding to our knowledge whether we thank BC or not!  My question:  Does this apply to the Canon 5D Mark II? 

 

I listen to you guy's arguments that demonstrated the superiority of the 6D over the 5D Mark II, but I was given a pristine 5D Mark II, and a 1.4x teleconverter, my Christmas gifts!  So, needless to say, I've gladly accepted it, and will finally experience the world of FF shooting!  I will attempt to look this up on the internet.  I just received the camera yesterday evening.  But, how great it would be if I could switch to the fast screen, with out having to be a camera tech. 

 

@ Wim, and Klaus (who made a reference in a different thread).  You have made comments that are thought provoking.  Being not at the level to really need to know how it's done, but still curious about MFA.  Wim, you mention that the lens is shimmed at the factory if necessary to adjust any back/front focusing inherent in the lens (paraphrasing of course). 

 

.....

Hi Arthur,

 

Just quoted the relevant parts.

 

Yes, replacing focusing screens with Canon alternatives is an option indeed.  I have the laser precision matte, which I ordered straight away with the order for my camera almost 7 years ago (5D II). I wanted it speciically for manually focusing my faster primes, plus my TS-Es and MP-E. I also had it on my 5D (mk I), and on the 1D Mk III .

 

Superiority of 6D is relative. It has slightly lower noise levels, but personally, I rarely shoot over 1600 iso, so it has never been a problem for me. The 6D is better in some ways, the 5D II in others. To really get a better camera in all aspects, you'd need to go to 5D III and up. However, 6D and 5D II are fine cameras with glorious image files regardless.

 

If this is your first FF camera, you may be totally surprised . In a positive way that is .

 

As to shims: what really happens is that camera mounts are shimmed, and focusing screens, or focusing screen holder systems, in such cases, are shimmed so that they concur with the standards set by the camera maker for accurate positioning of lenses and accurate focusing. They can be shimmed for exact distances and angles (the latter by using shims which are thinner on one end, and thicker at the other, in a gradual transition).

 

Lenses also are shimmed, again to make sure they are positioned correctly, for correct distance to manufacturer standard to the sensor, and for correct focusing distances.

 

These standards always have some leeway or standard deviation, and that may result in still not correctly focusing lenses (if the deviation is, f.e., both ways the same, the total may end up as being just too much for correct focus, or not at the sharpest point of focus). This is why there is MFA on many of the newer cameras, often on a per lens basis.

 

In addition, lenses are often also electronically adjustable,, which is generally something done at a service point, or even at the factory. This may be necessary of , f.e., a lens shows focus shift when changing from the widest aperture to a smaller one, like Canon did with my 50L and 85L II.

 

HTH, kind regards, Wim

[Arthur Macmillan]

Hi Arthur,

 

Just quoted the relevant parts.

 

Yes, replacing focusing screens with Canon alternatives is an option indeed.  I have the laser precision matte, which I ordered straight away with the order for my camera almost 7 years ago (5D II). I wanted it speciically for manually focusing my faster primes.

 

If thsi is your first FF camera, you may be totally surprised . In a positive way that is .

 

Thanks Wim, especially for the encouragement with the 5D Mark II.  And FF cams in general!

 

On to the shims.  My question really is this:  Can I just slide in in like a pizza into an oven or is it going to involve shims, and tests, and endless work.  I don't like procedures that cut into my shooting time.  So, which is it?  Pizza, or Journey to the Center of the Camera?

[wim]

Thanks Wim, especially for the encouragement with the 5D Mark II.  And FF cams in general!

 

On to the shims.  My question really is this:  Can I just slide in in like a pizza into an oven or is it going to involve shims, and tests, and endless work.  I don't like procedures that cut into my shooting time.  So, which is it?  Pizza, or Journey to the Center of the Camera?

 

It is just sliding it in like a pizza indeed, after removing the existing one obviously. Each focusing screen comes with a little tool to open the spring clip which holds the focusing screen in place, and it doubles as a pair of pincers to remove the old one and insert the new one, and obviously to close the spring clip again.

 

Takes literally 30 seconds to do when you have done it a few times.

 

Kind regards, Wim

[Brightcolours]

Lenses are NOT shimmed for accurate focus. Lenses may be shimmed to get the focal length correct and the infinity point at infinity, but with AF it has... nothing to do at all. A lens which needs adjustments concerning AF accuracy on a certain camera (often referred to lens calibration) will not get "shimmed"

 

Case in point: a lens with an extension tube can focus just fine.

 

About the 6D vvs 5D mkII: Not only does the 6D have a much better noise profile, without the 5D mkII trademark noise banding, it ialso has a more accurate AF system with more AF settings, WiFi remote live view.

[toni-a]

Lenses are NOT shimmed for accurate focus. Lenses may be shimmed to get the focal length correct and the infinity point at infinity, but with AF it has... nothing to do at all. A lens which needs adjustments concerning AF accuracy on a certain camera (often referred to lens calibration) will not get "shimmed"


Case in point: a lens with an extension tube can focus just fine.


About the 6D vvs 5D mkII: Not only does the 6D have a much better noise profile, without the 5D mkII trademark noise banding, it ialso has a more accurate AF system with more AF settings, WiFi remote live view.

Unbelievable how much you give importance to discussions and the level of patience you have.

I am not gonna discuss shimmed or not shimmed items.

Just to make you know that I still consider you a valuable contributor here, just I urge you (and everyone else) not to use harsh or humiliating language this is a photography discussion forum after all and absolutely no reasons to start any kind of war even if you don't like what another folk here is saying.

[wim]

Lenses are NOT shimmed for accurate focus. Lenses may be shimmed to get the focal length correct and the infinity point at infinity, but with AF it has... nothing to do at all. A lens which needs adjustments concerning AF accuracy on a certain camera (often referred to lens calibration) will not get "shimmed"

 

Case in point: a lens with an extension tube can focus just fine.

 

About the 6D vvs 5D mkII: Not only does the 6D have a much better noise profile, without the 5D mkII trademark noise banding, it ialso has a more accurate AF system with more AF settings, WiFi remote live view.

 

Lenses are shimmed for correct distance to sensor etc., and so that they indeed can achieve, amongst others, infinity focusing correctly. This has everything to do with focusing, and therefore with AF as well.

 

Lens calibration is just the electronic/digital part of the equation, to tell the AF system where to stop to get focus at the correct point. However, without an accurately "set" or shimmed lens, to make sure the lens plane is completely correctly aligned and has the correct distance to the sensor, and hence the AF system, that is often not possible. Lenses are not individually calibrated for mount distance, they are calibrated to a standard with a standard deviation, directly, electronically. In short, if shimming is not done correctly, they will not necessarily focus correctly, especially not with current dslr focusing systems (PDAF).

 

As to extension tubes: I guess you are joking. A lens plane still needs to be aligned correctly. And many lenses do NOT AF correctly with extension tubes. AF often is not precise enough for macro focusing. AFAIK, every manufacturer of macro lenses tells users to manually focus in close-up and macro situations, and not to rely on IS and/or AF.


As to the noise profile: I prefer the extra few MPs over the slightly lower oise, as indicated I rarely shoot over 1600 iso anyway. And 6400 iso is eminently usable on the 5D II, FYI. As to the "trademark noise banding": have you personally actually ever used a 5D II yourself and indeed have had any images ruined by it? I guess not. Funnily enough, never have I. I happen to have been shooting a 5D Mk II for 7 years now.

 

I think you may take certain comments on the internet too serious, every so often.

 

As mentioned before: in the end it is the photographer who creates the photograph, not the tool, i.e. camera, used to record an image.

 

Kind regards, Wim

[toni-a]

Well for macro I found live view extremely helpful, I use it every time I do macro for many reasons:

1) Most important I don't have to lay on the ground or get uncomfortable while shooting,

2) I don't cause lighting issues with my own shadow

3) mirror is already locked up

4)Focus is extremely reliable especially when zooming (focus peaking)

5) I can reliably preview exposure with exposure simulation

[Brightcolours]

Lenses are shimmed for correct distance to sensor etc., and so that they indeed can achieve, amongst others, infinity focusing correctly. This has everything to do with focusing, and therefore with AF as well.

 

Lens calibration is just the electronic/digital part of the equation, to tell the AF system where to stop to get focus at the correct point. However, without an accurately "set" or shimmed lens, to make sure the lens plane is completely correctly aligned and has the correct distance to the sensor, and hence the AF system, that is often not possible. Lenses are not individually calibrated for mount distance, they are calibrated to a standard with a standard deviation, directly, electronically. In short, if shimming is not done correctly, they will not necessarily focus correctly, especially not with current dslr focusing systems (PDAF).

 

As to extension tubes: I guess you are joking. A lens plane still needs to be aligned correctly. And many lenses do NOT AF correctly with extension tubes. AF often is not precise enough for macro focusing. AFAIK, every manufacturer of macro lenses tells users to manually focus in close-up and macro situations, and not to rely on IS and/or AF.

As to the noise profile: I prefer the extra few MPs over the slightly lower oise, as indicated I rarely shoot over 1600 iso anyway. And 6400 iso is eminently usable on the 5D II, FYI. As to the "trademark noise banding": have you personally actually ever used a 5D II yourself and indeed have had any images ruined by it? I guess not. Funnily enough, never have I. I happen to have been shooting a 5D Mk II for 7 years now.

 

I think you may take certain comments on the internet too serious, every so often.

 

As mentioned before: in the end it is the photographer who creates the photograph, not the tool, i.e. camera, used to record an image.

 

Kind regards, Wim

You again write a lot without being correct in any point. 

 

Calibration does not touch on telling the lens where to stop to achieve focus. It calibrates the steps a lens makes. The AF system can see when something is in focus, but does not check the end and leaves that to a rightly calibrated lens, for speed purposes (the camera manufacturers do not want a hunting game at the end, where focus is never really achieved).

 

The flange distance is only of interest for reaching infinity and determined MFD. It has no bearing what so ever on AF or AF accuracy. Again, see extension tubes (lenses work just fine with them, despite what your typing suggests).

You have no clue on how PD AF actually functions on DSLRs...  :ph34r:

 

The noise banding the 5D mkII gives is very widely known. The 5D mk II in my opinion is a nice tool, but in sensor output the 6D has passed it by some margin. 

[Arthur Macmillan]

"The noise banding the 5D mkII gives is very widely known. The 5D mk II in my opinion is a nice tool, but in sensor output the 6D has passed it by some margin. "

 

I don't doubt what you are saying.  I had decided, back when the prices were not that far apart to get the 6D.  Now I would be tempted to look for a 5D Mark III on the used market. 

 

But getting a pristine 5D Mark ii for $215 is too good to pass up.  This camera doesn't even look used, and it is from someone I know who just wanted to make a FF camera available to me, not a seller who prepped it to sell.  She even let me borrow her 17-40mm F/4L and I high end Tamron VC zoom.  So, by my way of thinking, that plus a 1.4x Tamron SP autofocus compatable teleconverter for $10, I got a whole lot of toys to play with for a total of $225.  I refuse to mourn my bad luck in not getting a 6D!

 

As to the effect on AF of moving the focusing group relative to the focal plane, and your example of being able to focus using a tube - and please, I do see your point!  I just wonder in an innocent beginner way if there might not be some effect on AF as there would be some effect on depth of field.  A will throw in yes, for a very small amount, the effect on DOF is corresponding small.  That was just conjecture 1.  Conjecture two - Again, I'm just guessing...not saying... but MFD is something the might be fixed physically, even if I know infinity focus most often is not.  If an algorithm assumes closest focus to be minimum focus, and it is not, well who knows.

 

All that said, you are probably right.  I'm am just hoping for the day the MFA can be automated.  In fact, I've seen products that seem to claim this ability.  I think it is software plus a target.  But I am hoping someone like you figures that one out.  Complicated stuff to me!

[Arthur Macmillan]

@ Wim:  You are hardly the one I would challenge when it comes to macro work!  Not if you run around with the 65mm MPE!

 

I did forget to mention in the above comment that you are indeed correct, many lenses do no focus correctly with tubes attached.  What makes this tolerable is the fact that your higher magnification at least allows you to see more details, if you have good lighting.

 

The same thing could be expected with anything changing depths of field, such as close-up lenses.  Which is why (Just guessing) close-up lens work better further away from the subject.  Because the size of the focus steps will be off, hence Canon's advice, that AF even using their doublet closeup lenses is not recommended.  Now, it comes down to scale.  Is there enough difference to make a difference.

 

Let me throw in one example why I think the answer is maybe yes.  Even decent quality adapters from Pentax, Nikon, M42, and Tamron Adaptall-2 to EOS.  Often loose infinity focus.  This is regardless of the quality of the lens in question.  It can only be the adapter, and the adapter is not off by very much!  One that looks identical to the eye, might give perfect results.  So, it just makes me wonder, that's all. 

 

Of course I don't need to understand perfectly how the system works.  But one speculates on one's hobby.  It's human nature.