a100 vs a700 -- Exposure Metering

[chriznatch]

Last night I took a number of pictures with my a100 using a Tamron 17-50 lens and the HVL-56am flash unit. Although we had a few lights on, the room was fairly dimly lit. I set the aperture at a variety of settings ranging from 2.8 to 5.6, ISO at 400, turned the flash on and pointed it directly at my subjects with no diffusers of any kind, and let the camera choose the shutter speed. The result: all of my pictures came out very dark. All of them were at least one stop underexposed. Even when I added +1 exposure compensation, the pictures were still fairly dark. All of them looked good in the LCD window, by the way, but once I got them on my computer it was clear that they were very underexposed.

The only way I could get a close-to-properly exposed picture was to go to full manual mode and set a much slower shutter speed than the camera was choosing.

The same thing happened to me the night before using the Sony 50mm 1.4 lens, so I know it's not a lens issue.

I should add that DRO was turned off.

The bottom line is that I can ultimately get the correct exposure, but with this camera it often takes a lot of trial and error to do it. And along the way, I miss a lot of good pictures.

My main question is whether the Sony a700 is better at exposure metering than the a100. I've been thinking of upgrading for awhile now, but if the a700 doesn't improve in this area, I don't know if it's worth the $$, since exposure metering is pretty much my only gripe about the a100.

Any words of wisdom would be much appreciated!

Chriznatch

[David Kilpatrick]

You would have to post examples of the photos for any useful comment. The flash metering is very sensitive to reflective highlights.

David

[chriznatch]

I think I discovered the problem. First, as you suggested, there was a reflection issue -- the backdrop for all the pictures was a cinderblock wall painted in glossy white paint. Second, I had the exposure compensation set for ambient only. Tonight I changed it to ambient plus flash, added plus 1 in exposure compensation, and tried a few test shots in the same room. They came out much brighter and with a better exposure. So as usual with my pictures, it was user error rather than a defect in the camera. (Not that that will stop me from blaming the camera the next time I mess up some pictures!)

Anyway, thanks for the insight. I'll spare you the sight of my mangled pictures now that I know what I was doing wrong.

[Javelin]

does changing the metering mode make any diference in this situation ? say you used centre weighted instead would it have exposed the subjects better?

[chriznatch]

I'm guessing it would help, but it didn't occur to me to try it the other night. In the past, I've tried exposure lock + spot metering, and that has helped sometimes. I'll test the center-weighted metering tonight and see how it works. Thanks for the suggestion

[adakshi]

I'm guessing it would help, but it didn't occur to me to try it the other night. In the past, I've tried exposure lock + spot metering, and that has helped sometimes. I'll test the center-weighted metering tonight and see how it works. Thanks for the suggestion

If you are using 'D' lenses, use ADI flash instead of TTL, it greatly reduces reflection problem, at least in A700, I need to check in A100 though.

Thanks
Ayan