Does a full frame see less light?

[snapshot2011]

I have a question.

I have a 60D, 5Dmark2, 580exmk2 and 24-105.


Querie is this.

If I take a photo with 60D, speedlite and focal length at say 24mm, all flash settings set to default, the final image looks good. Not over or under exposed.


Now......if I take the 5d and setup exactly as the 60D shoot and take a shot, the resultant image seems underexposed. Its as if the flash didnt illuminate enough.

Is this just a moving up to full frame thing or have I an issue? To counter act this, I have to increase my FEC by +1 to get near to the 60D look.


Please clear my thoughts about this

[KCY]

How is the flash configured? E-TTL or Manual?

I would have thought they should see the same amount of light.

[gonzogolf]

No, they should perform the same at the same settings. The problem could be a couple of things. The first is how are you measuring this underexposure? Histogram, or just the LCD? Are you putting the camera in the same place with this test? If so the wider frame of the FF camera may cause it to meter differently than the crop camera because its seeing a different set of elements which may fool the meter. Are you certain you are using the same metering pattern?

[gonzogolf]

Originally Posted by KCY

How is the flash configured? E-TTL or Manual?

I would have thought they should see the same amount of light.

If he is using FEC, its ETTL as there is no exposure comp in manual.

[KCY]

Originally Posted by gonzogolf

If he is using FEC, its ETTL as there is no exposure comp in manual.

good point

[Numenorean]

Different cameras expose slightly differently at the same settings. It shouldn't be a ton - like a 1/3 of a stop difference or something, but it's just how things are.

[snapshot2011]

same position for everything, just one is crop and other FF.

Flash mode is E-TTL II

I have reset all setting on both bodies and still the same

Not sure why this is the case

[snapshot2011]

will research a bit more

[gonzogolf]

Originally Posted by snapshot2011

same position for everything, just one is crop and other FF.

But they arent seeing the same thing from the same position. The field of view difference between the two will mean the FF camera would be metering scene elements that are not present in the crop's field of view.

Try the same experiment with the camera and the flash both in manual. This is a metering issue more than it is a light recording issue.

[Scatterbrained]

If you're shooting from the same position, are you framing the subject the same, i.e. using a longer focal length lens to counteract the wider field of view?

[MrScott]

Make sure both cameras are set to the same ETTL metering mode?

The following is an old post with examples that also may help explain w/ pics.
http://photography-on-the.net/forum/...53&postcount=7

[JakAHearts]

Originally Posted by MrScott

Make sure both cameras are set to the same ETTL metering mode?

The following is an old post with examples that also may help explain w/ pics.
http://photography-on-the.net/forum/...53&postcount=7

This.

[TheBrick3]

In my experience, the light sensitivity of cameras does vary. I look it more as technical falling of the metering than an actual difference between the cameras. I remember that my 40D used to demand less light to take the same picture as my 5Dc in low light, but the 5Dc seemed to get a better exposure while the 40D used warmth to make up for under exposure.

[Wilt]

If you really research flash threads on POTN, back 6-8 years ago it was very common for photographers to have to dial in FEC +1 by default, in order to get a flash exposure with the same density as might be obtained via ambient-only shot (on tripod). That was true on my 20D. Then, with my 40D and the same flash unit, on ETTL it was no longer necessary for me to dial in FEC +1 by default!

The OP has a 5DII, however. The difference in flash density very well may be attributed to the camera's flash programming, and how it decides about what zones to bias, etc. in commanding the ETTL flash to output a certain amount of light.

In order to prove that a larger format camera does NOT 'need more light', the flash should be put on Manual flash (not ETTL), and the cameras should be set with a manual shutter speed and aperture, and a flash shot taken with each camera...the results should be nearly identical for density.

Keep in mind that in a true comparison, one needs to keep in mind the need to choose FL to suit the format size! So if you use 30mm lens on APS-C (2 * frame height), you need to use 48mm or so on FF (2 * frame height), to frame the same area from the same camera position.
Also keep in mind that the zoom head of the flash may not be truly 'equivalent' in coverage area, when switching between two formats. So a way to eliminate that as a possible variable is to simply set the zoom head at a fixed wide position (like 20mm) for both formats, so that flash coverage angle is identical for both shots.

[snapshot2011]

tests were conducted in manual and flash bounced off ceiling.

I have made the test very fair, but the 5d just doesn't see the light like the 60d does