topic Re: 5D Mk III LCD auto-exposure compensation?! in EOS DSLR & Mirrorless Cameras

5D Mk III LCD auto-exposure compensation?!

billium99 — Thu, 05 Feb 2015 21:22:09 GMT

Hi - I have the 5D Mk III and I'm confounded by one thing the camera does that I can't seem to prevent. No matter what setting I try in M mode, if I manually open or close my lens aperture, my LCD preview compensates to give me some kind of neutral exposure, but this is completely inaccurate from the final photo taken.

Why does the camera do this by default? I get that LCD preview is not a great, accurate way to guage how the photo will look, but I'm just looking for a ballpark estimation of exposure, and instead, I basically have to snap photos, adjust, snap more photos, etc because the LCD preview doesn't help me.

Am I missing an obvious setting somewhere? I've tried WRENCH > LCD Brightness and set to manual, but this doesn't nothing to help with this exposure compensation.

Any suggestions?

Thanks

Bill

Re: 5D Mk III LCD auto-exposure compensation?!

ebiggs1 — Fri, 06 Feb 2015 14:45:36 GMT

Bill as you stop down the lens it will get darker. That is where it is getting it's light from. It is not meant to be a light meter, however. Even the view finder will get darker and it isn't a lightmeter either.

Re: 5D Mk III LCD auto-exposure compensation?!

RobertTheFat — Fri, 06 Feb 2015 14:55:40 GMT

@ebiggs1 wrote:
Bill as you stop down the lens it will get darker. That is where it is getting it's light from. It is not meant to be a light meter, however. Even the view finder will get darker and it isn't a lightmeter either.

That doesn't sound right to me. Bill is undoubtedly using a preset lens, which doesn't stop down until you push the shutter button. So everything looks as it would at full aperture. To see the actual intensity of hte light (at least to the extent that the LCD preserves it), you'd have to push the preview button. Or am I missing something obvious?

Re: 5D Mk III LCD auto-exposure compensation?!

ebiggs1 — Fri, 06 Feb 2015 15:04:08 GMT

You may have a point and be right. I assumed he was using a lens that actually stopped down in manual. I don't know what else would cause the LCD to darken as you stop it down.

Re: 5D Mk III LCD auto-exposure compensation?!

billium99 — Fri, 06 Feb 2015 15:11:35 GMT

Hi Guys,

Thanks for the time!

Yes I'm actually using some Zeiss zf primes with de-clicked apertures, so I'm manually stopping down.

But...what I'm saying is - my LCD get's darker momentarily, then compensates and "normalizes" the exposure shown in the LCD window. If I open it up, the LCD gets brighter momentarily, reflecting my change, but then lowers the exposure in the preview.

This does not affect the final image. But that's the problem. I can't get an accurate preview or anything even close to accurate, in the LCD screen if I'm experimenting with exposure parameters.

Does that make more sense?

Bill

Re: 5D Mk III LCD auto-exposure compensation?!

ebiggs1 — Fri, 06 Feb 2015 15:17:03 GMT

Yes it does make more sense and it is normal. The LCD is not a light meter and the camera is adjusting it for your ease of use.

It is totally electronic and not meant to be an actual result of the picture. It is like a TV or computer monitor.

Re: 5D Mk III LCD auto-exposure compensation?!

billium99 — Fri, 06 Feb 2015 15:42:28 GMT

Well I agree that appears to be their design intent - I don't agree that it should be the case that a "preview" should look completely different from the actual result. I'm not using it as a light meter. I'm using it as a preview approximation. And in this context, it fails for me.

Thanks again for your time.

Bill

Re: 5D Mk III LCD auto-exposure compensation?!

PhillRoath — Fri, 06 Feb 2015 16:03:17 GMT

I can only speak for the T3i, but mine does what you are asking for. It does it in M mode with the ISO set to a value (not automatic). I can sit here at my computer in live view and see the image on the LCD lighten or darken as I change settings, (e.g. chane the shutter speed).

As soon as I switch to Av it only does a small amount due to the limited f/stop range of the lens. With Tv mode, from a normal viewed picture on the LCD increasing the shutter speed darkens the image. At 1/1250th, the LCD is so dark I can barely make out the image.

Again, this is with my T3i. YMMV

Is this what you were asking?

Phill

Re: 5D Mk III LCD auto-exposure compensation?!

billium99 — Fri, 06 Feb 2015 16:13:00 GMT

Hi Phill - yeah precisely.

And the 5D Mk III, in M mode, isn't doing what your T3i is. Or rather, it does appear to show a "fixed" adjustment if I change shutter speed or even if I radically change ISO.

But if I manually move my lens aperture, it "fights" the adjustments in the preview window, and gets further and further away from an accurate preview.

Not very helpful, imo

Bill

Re: 5D Mk III LCD auto-exposure compensation?!

RobertTheFat — Fri, 06 Feb 2015 16:48:54 GMT

@billium99 wrote:
Hi Guys,

Thanks for the time!

Yes I'm actually using some Zeiss zf primes with de-clicked apertures, so I'm manually stopping down.

I stand corrected. That's what I get for guessing.

But...what I'm saying is - my LCD get's darker momentarily, then compensates and "normalizes" the exposure shown in the LCD window. If I open it up, the LCD gets brighter momentarily, reflecting my change, but then lowers the exposure in the preview.

This does not affect the final image. But that's the problem. I can't get an accurate preview or anything even close to accurate, in the LCD screen if I'm experimenting with exposure parameters.

Does that make more sense?

Bill

Since I had my 5D3 manual handy, I decided to see if it would throw any light (pun intended!) on the issue. It seems that the LCD has both automatic and manual brightness settings (p. 285 in the Feb 2013 edition). While it doesn't come right out and say so, I think the implication is that if you use one of the manual settings, it won't apply a correction, but will let the brightness vary with the strength of the incident light. It might at least be worth trying if you haven't already done so.

Re: 5D Mk III LCD auto-exposure compensation?!

PhillRoath — Fri, 06 Feb 2015 17:05:23 GMT

One more thing. I just downloaded the 5D Mk III manual and on page 203 it speaks of Final Image Simulation (page 202 speaks of Exposure Simulation). On page 203 down below it says "Exposure (with [Expo. simulation: Enable]) and page 207 shows how to enable. Perhaps this is not on?

My T3i does not allow me to change this, it is always on.

Phill

Re: 5D Mk III LCD auto-exposure compensation?!

billium99 — Fri, 06 Feb 2015 18:13:57 GMT

Jumping beans that was it!

Phill I appreciate you looking in a manual for a camera you don't own, to help a newb out! I feel bad that I didn't find this, but take some solace from the page number...

This is a lesson in trying the manual before trying Google or forums, although I'm pretty sure I read about Exp Sim and thought I had it set correctly as Disabled. But in fact, I reversed that setting and have exactly what I was after.

Thanks again!

Bill

Re: 5D Mk III LCD auto-exposure compensation?!

billium99 — Fri, 06 Feb 2015 18:16:38 GMT

Thanks Robert - that is for the overall LCD brightness, rather than the exposure. I did find that setting, but it wasn't what I was after. The update is that Phill found it. It's Exposure Simulation, which I think I'd seen information about, but incorrectly assumed that "Disabled" was the correct setting. Instead, it needed to be "Enabled".