Heavy underexposure when I thought I was going to over-expose?

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vaizki

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Jukka
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Was out today with my old battleship 1Ds + 35/1.4L that I just got, and just did some snaps in the car park to test what kind of shutter speeds I'm looking at wide open..

So there's snow about and the sun is shining. In Av mode at f/1.4 and ISO 100 the camera is flashing 8000 in the viewfinder and to me that's an indication that even at 1/8000s exposure (camera max) it's going to be overexposed. Well why not let's see how much.. KLIK.

And in the evening, at the computer, this is what I get :eek:

1194284936_x5E6s-L.jpg

Canon 1Ds, Av mode, EF 35/1.4L, f/1.4 (set), 1/8000s (camera choice), ISO 100 (set), Evaluative metering

I know I know.. "don't do that".. and I usually don't.. but what's going on here? :thinking: It's at least 4 stops underexposed... So 1/500s would have been fine pretty ok.. Is my 1Ds busted? It's never done this type of thing before.
 
The snow and light was fooling your metre you should allways use compensation of approx' +1.5 to 2,;)
 
Well as I said, this is about 4 stops underexposed and the camera was blinking the shutter speed indicating it wanted to underexpose even more. And the car is covering most of the frame..

Living in Finland, I'm painfully aware of how metering and snow work together :naughty:

And here's the histogram.. untouched.. weird metering if it thinks that's ok :)

1194482664_5ysKH-O.gif
 
Couldn't you take a test shot of something else?
 
HoppyUK said:
Couldn't you take a test shot of something else?
Click to expand...

If you've ever used a 1Ds, you know that you DON'T review pics out there, but bring them indoors :)

It takes like 8 seconds for the image to display and the screen is a completely useless POS in any kind of sunlight. So I didn't realize this happened until I got back home. But I *did* find another dud there actually, here goes:

1194574826_E2WMC-L.jpg

Again, Av mode, ISO 100, f/1.4 and 1/8000s.. :shake:

Now this one is closer to 7 stops underexposed :D There's a road, cars, some forest, sky and yes a bit of snow in the pic. Trust me.

And yes I was shooting RAW as always.. Good call on the focusing screen but no bonus, the setting is right ("normal" screen).

I'm starting to think that the camera logic is just failing completely in special circumstances. I'll have to start checking the screen.. oh and using an ND8 at least when shooting f/1.4 in bright sunlight..
 
What I meant was, shoot something where there is not potential for incorrect exposure in the first place. Using the Sunny 16 rule, and taking other things into acount, the exposure setting doesn't seem that far off to me. But there looks like a lot of depth of field in that first shot for f/1.4. Aperture diaphragm problem?
 
Interesting idea with the aperture.. but the aperture would be fully open when composing, and with Av and f/1.4, it would not be stopped down at all... so how would it end up at f/5.6 or f/16.. :shrug:

For a DoF comparison, here's another f/1.4 shot of a car (same lens but on a 5D). As you can see 35mm is pretty forgiving.. :thumbs: Focus was on the rear corner of the side window.

1194611117_5Eh7o-L.jpg

(not my car.. but the yellow one is)

Of course, close up the DoF is thin.. very thin.. and the perspective distortion starts to show.

1194438580_MT9uH-L.jpg


Ok now I'm just pasting stuff to show the lens works.. this last one is 1Ds, ISO 640, Av mode (always!), f/1.4 and 1/80sec.

1192253897_Q7Kpm-L.jpg
 
RX-8? :)

Aperture is electronically controlled, so it could be doing anything if it's faulty. Easy enough to check if it's stopping down when you shoot. The lens is new, yes?

Try a the same shot/settings on a few different camera/lens combos. Should isolate any problem, if you've not gone too far down that bottle yet :D
 
Hoppy, will do some more tests for sure. Didn't notice any stopping down - and I would on the 1Ds bright viewfinder..

Jim, the yellow one (mine) is indeed an RX-8 as Richard correctly points out ;) The merc is obvious..
 
I just spotted it after i posted, it's me that needs the sleep!
 
Was there a bright reflection perhaps fooling the meter?
 
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