5D Mkll & 580EXll question

rwells

I've got a question for those that now own the 5DMkll & a 580EX/EXll:

I pulled out my speedlights (1) 580EX (2) 580EXll and was doing a little shooting around the house with one mounted on my 5DMkll. I quickly found something that I cannot explain, but can replicate with any of the (3) speedlights on this body.

I've tried many settings, but lets use this one:

Camera:manual exposure settings:ISO 400, 1/200, f/4 - FEC 0 - flash on = Shots inside house are all 1 2/3 ~ 2 stops underexposed per histogram (both displayed, RGB & brightness).

I have reset all Cf.n to defaults on all three speedlights. This happens consistently with all three speedlights. I can immediately put said flash(s) on my 5D, change to the same lens, take a shot = correct exposure with FEC 0.

I have tried all known (to me) settings with 5DMkll body. (eg: highlight priority on/off - etc...)

Will someone with both bodies (pathfinder) please check this out on your camera's/580EX(ll). Or, for that matter, anyone with the new 5DMkll and 580EX/ll, does your setup correctly expose flash shots with FEC set to 0?

I can compensate with FEC +1 2/3 and get consistent correct exposures, but that's something that I don't want to have to do. That shouldn't be required.

I'm hoping that there is some setting that I'm just missing that's causing this, otherwise, the body may be on the way to Canon for resolution.

Thanks in advance.

pathfinder

Give me 24-36 hours and I will check this out Randy.

Kinda busy right now:D

Merry Christmas!

rwells

pathfinder wrote:

Give me 24-36 hours and I will check this out Randy.

Kinda busy right now:D

Merry Christmas!

Thanks Jim,

No big rush...


Merry Christmas to you and yours!

pathfinder

Randy, I sat down this afternoon with my 5D MKll, a 580ex II, a 580ex, a 24-105 f4 IS L, and a Kodak gray scale to see if I can replicate what you are experiencing. I agree that something funny is going on. I shot several frames in RAW and verified that you do need some degree ( > +1 stop FEC ) but shooting RAW introduces what is the proper ( Auto ACR or Default, or custom processing or what ) jpg, so I reshot with 'out of the camera jpgs' with a 'Standard Picture Style' set in the camera.

I shot four jpgs, 2 with the 580ex II, and 2 with the 580ex. All were shot at ISO 200, f5.6 1/160th to minimize ambient light. I shot in Manual Mode and spot metering and metered off the gray border on the Kodak Gray Scale, with the flash in ETTL pointing directly at the subject. I used no FEC in the first frame for each flash, and + 1 2/3s for the second frame.

Each jpg shot with + 1 2/3s + FEC showed blown highlight blinkies in at least two bars in the jpg histogram on the camera LCD, but when you read the pixel data in Photoshop CS3, none of the highlights read as fully blown in any of the R<G or B channels. But even the 0 FEC shots do not measure as underexposed as 1 2/3s of a stop. I am not sure I fully understand exactly what is going on here, so I shot a fifth shot much closer to the gray scale again at 0 FEC with the 580ex, and find it looks pretty good, even if a touch under exposed

Here are the unprocessed jpgs..... The RGB values in the highlights and shadows are read in PS with the eyedropper

580exII 5DMkll SFC ( straight from camera ) 0 FEC




580exII 5DMkll + 1 2/3s FEC




580ex 5DMkll SFC 0 FEC



580exII 5DMkll + 1 2/3s FEC The highlights look blown, but do not read that way at the pixel level




And finally, here is a closer shot of the gray card, metered with a spot meter, and 0 FEC with a 580ex. I think this one is about a stop under myself



All flash settings were set on the flash itself, NOT via the camera menu, but the proper readings were present in the camera menu for flash settings. I think maybe + 1 2/3s FEC is a bit hot, but +1 to 1 1/3s +FEC is very reasonable. Not sure why though, Randy. I have not tried this experiment with any other bodies yet.

I am interested in comments, criticisms, opinions etc.

DI-Joe

I shot a wedding yesterday with my 5D MKII, 580EXII and a plethora of lenses. Shooting in manual mode I didn't have to tweak anything, almost every shot came out as expected...

rwells

Jim,

First, thank you very much for taking the time to do some testing with your gear for me.

Looks like another Canon mystery to me


I am a Canon fan & have made my living with them for the last couple of years, but man, I wasn't expecting a guessing game with this new body. As you know, it was hard enough to get to know the Canon speedlight system intimately, and now to have to perform mental gymnastics to use their speedlights with the new body, well...:cry


Alas, I still may be getting the cart in front of the horse here. Will have to do more in-depth testing myself, but their certainly appears to be a fly in the ointment here. I'm hoping that's with my not understanding the new 5D Mkll body & the new functions fully, but I have my doubts after seeing your test.

Strange; seems to be a significant difference in your test with the two different flash's results, hmmm...

Again, thanks for your time and effort. I'll add to this post when I have done more testing.

rwells

DI-Joe wrote:

I shot a wedding yesterday with my 5D MKII, 580EXII and a plethora of lenses. Shooting in manual mode I didn't have to tweak anything, almost every shot came out as expected...

Thanks for your input.

Question: When you shoot weddings, do you slightly underexpose images? Would this be why "almost every shot came out as expected...", or were the images intended to be "exposed to the right" with 0 FEC, and they came out "exposed to the right". Two different things. --- Just trying to narrow down your experience.

Also, what were the camera & flash Cf.n settings? Highlight tone priority. Auto lighting optimizer.

Reason for question: I will shoot some events/shots underexposed on purpose, personal preference. Sometimes to ensure I don't blow highlights, other times for color saturation, etc. But, I want to be the one in control of any underexposure, not my camera.

My 5D allows this in a logical manner. My 5DMkll, well... I'm still looking into it.