Well Documented Live View Exposure Simulation Issue

[DevApple]

I'm including a number of links which document this issue across multiple canon cameras. After doing a search on the canon forum, I can't find this particular issue, so I thought I'd post and see if we can get an official solution. (New to the Canon forums, so if I'm not looking in the right place, please let me know.)

In my opinion, the vimeo link illustrates this best. (and while the 2nd link says "solved" ... perhaps the solution could be described as "janky" at best.)

Basically, from what I can gather: The Live View (*in photo mode) uses the lens's aperture data to update the exposure simulation parameters. This effects the way the LCD and the Histogram interpret exposure settings. If you are using a lens without these digital chips, the Exp. Sim. parameters don't get updated and the liveview/histogram will sometimes appear under exposed when compared to the actual photograph (anywhere from -1 to -4 stops from what I've seen).

What's strange is that this problem disapears in video mode. Perhaps I don't understand the real issue, but it sounds like a firmware update is needed. Is there an update available(or will there be) that fixes this problem?

https://vimeo.com/43633270

http://www.dvxuser.com/V6/showthread.php?246032-dark-live-view-on-T2i-550D-when-using-vintage-manual...

http://www.dvxuser.com/V6/archive/index.php/t-247001.html

[DevApple]

At least on my 60D, you can turn off exposure simulation - it helps, but that's not really a great solution either.

People have suggested buying body caps with "focus chips" embedded in the ring - you just pop the cap on before switching to your manual lens and it updates the aperture setting to 1.4 or something. I'm not sure why that fixes the problem, but people say that it does. (i guess it still works even when you have the manual lens set to a high T-Stop)

I suppose the Video mode doesn't use exposure simulation, so that's probably why it works while the photo mode doesn't.

Would love to hear back from Canon about this - and sorta put this issue to rest.

[cicopo]

If I understand your messages correctly you seem to think it's Canon's responsibility to make sure their cameras work perfectly with lenses from other manufacturers. That's like me asking Ford to pay to have my Chevrolet modified so I can install Ford tail lights. Canon clearly says their cameras require EF & / or EF-S lenses, not any lens someone might wants to use.

[DevApple]

This problem exists with EF lenses. Including Canon Brand Lenses that do not have the Focus Chip (We're talking vintage lenses.) The non EF lenses that use old EF adapters also have the problem, but Canon lenses are not exempt.

[DevApple]

I guess the old canon glass was called an FD mount, so your point is valid - but the issue remains.

I suppose the mere fact that this would increase the value of all EOS cameras is reason enough for canon to consider this update - If it's even a possible fix. Regardless it wouldn't be unheard of to have aftermarket embraced by the manufacturer. To use your car example - Ford Mustangs and Shelby Automotive. But I digress - This is something many users would like to see. I'm asking 1. Is it possible, and 2. Is there already an official solution(or will there be).

[TCampbell]

While it's an interesting and puzzling issue as to why it works the way it does, I'm not sure it's a problem.  It sounds more like an academic curiosity.  

The Vimeo video demonstrates using a non-Canon lens that has no contacts.  FD lenses aren't compatible with EOS cameras.  I own FD lenses, but these aren't designed for EOS bodies (they work great with my old AE-1 though).  Even though it is possible to use adapters to allow them to mount, ther camera cannot control the aperture and of course they're not auto-focus lenses.  There's not much reason to ever try to adapt one to work on an EOS body (it would need to be a phenominal FD lens to make it worthwhile.)  FD lenses are not intended to be compatible -- so when someone reports that they're not compatible, this is not exactly a surprise (nor a reason for concern).

Do you know of a Canon "EF" or "EF-S" lens for which this issue exists?

[DevApple]

The issue only exists with chip-less lenses- but it's a problem with ALL chip-less lenses. Even "EF" mount type lenses manufactured without chips. (Canon doesn't do this, but the vimeo example shows a rokinon 14mm EF style lens). The user's comment is correct- canon does not warrant the use of these 3rd party lenses, but as the only dslr manufacturer with this issue, I see it as a good reason to try a Nikon body for my next purchase. Third party lenses make up the bulk of the available lens market, and i expected canon to be a bit more "open sourced" about their products. But i guess lens sales are an important revenue stream and make that prohibitive.... Or maybe it's as simple as: it's not possible? I guess that's the real question i'm asking. And yes, at this point the question feels academic, but maybe it doesn't have to be? Firmware update?

[TCampbell]

If I understand you correctly... you're referring to a 3rd party lens designed to fit on a Canon EOS body as an "EF" lens -- not actually suggesting that Canon themselves make a lens that has the problem.  

Niether Canon nor Nikon (nor anybody else that I am aware of) release the specs to 3rd party lens makers.  Those 3rd parties reverse-engineer the cameras in an attempt to build compatible lenses.  Again, I'd stress that to my knowledge, ALL camera makers are the same in this respect.  It is not a differentiator.  

Rokinon (and the same lenses are sold under a variety of names) is known for their very cheap lenses.  It's a bit of a case of "you get what you paid for."  

I don't work for Canon so I'm not trying to argue that you should only consider Canon products.  (I do like their products and am happy with all of my Canon gear.)  But I would probably not reduce my camera buying decisions be decided by just this one feature alone.  There are are so many aspects to consider when buying a camera.  Is this really that important to you?  

The guy in this video is using a Canon 5D III.  That's a $3500 camera body.  Realistically, no photographer who can afford a $3500 camera body is going to shoot with a Rokinon 14mm lens -- and then have the audacity to expect that it's Canon's fault when the cheap lens isn't fully compatible with the high end $3500 body.   😕

There are a number of 3rd party lens makers... Sigma, Tokina, Tamron... and then there are some very high end lens makers... Schneider, Ziess, etc.   But when these lens makers build lenses for the cameras, they actually do tend to work correctly (not always... and sometimes a lens that worked with one body might not continue to work years later when Canon comes out with newer bodies... but Canon's own lenses DO work EVEN when you upgrade camera bodies.  Canon makes certain of that.)

Rokinon, however (and the same lenses are sold under multiple names... Samyang, Bower, Pro-Optic, etc.) are known for their especially cheap, basic, low-end lenses.  If you are going to buy an exceptionally cheap, basic, low-end lens... you should probably not be at all surprised to learn that there are limitations.   Notice, for example, that the lens has an aperture ring on the lens... modern lenses don't do that anymore.