What is the right ISO for A700?

[sury]

Yesterday I took some flash shots with A700 (barely a day's worth of familiarity) and found them to be noisy.
When I looked at the ISO, I found that the camera set it to 800. I figured out after a bit of experiement that A700 defaults
to IS0800 for flash in Auto mode. I don't know whether it is a feature or an annoyance. I don't think A100 did that.
What should be the ISO setting on A700 when shooting with flash? As low as possible? A set number? Any suggestions are
appreciated.

With best regards,
Sury

[David Kilpatrick]

I normally use 400 for bounce flash. It makes a big difference.

David

[sury]

David,
Thank you. Just curious. Why not the lowest setting?

With best regards,
Sury

[David Kilpatrick]

Only use the lowest setting for direct flash. If you use bounce flash, the guns do not have enough power for even f4 in a normal room at ISO 100. ISO 400 means you can use f5.6 in most domestic rooms, f8 in smaller rooms, and f11 in rooms with white ceilings and very small dimensions like a bathroom. Do not use Program for flash. You will always end up at full aperture with most lenses and it sucks. Use Aperture Priority, set f5.6 and 400 ISO for bounce, and if in doubt, set DRO +3 and shoot JPEG as well as RAW. DRO+ can make a big difference to underexposed flash shots.

David

[bakubo]

David, does your advice above about using ISO 400 also apply to the smaller HVL-F36AM flash?

I almost never use flash, but I got the HVL-F36AM new a few months ago for US$59 at Best Buy. Strange, but in 35 years of using FSLRs and DSLRs, for the kind of photos I take I just don't use flash hardly at all so don't know that much about using it to good effect. My last flash was the 3200i that I bought at the same time as the 7000i in 1988. Before that I had a Vivitar (don't remember the model) with bounce which I bought in 1986 for my X-700 and I'm not sure I ever even used it. Before that I had a Spiratone thyristor flash I bought in 1974 for my first SLR, a Mamiya/Sekor 1000 DTL. I did use it some, I was a teenager at the time, but just direct flash and just learning. By the way, I still have all of those flashes. A few months ago I took out the Spiratone, plugged the AC adaptor/charging cord in, and popped off a couple of full power flashes using the rear flash button. Sure seemed to be working just like new. Didn't check to see if the batteries would still hold a charge though. By the way, this flash was pre-hotshoe.

Darn, I must be getting old. Everytime this sort of thing comes up I start feeling nostalgic and write a bunch of useless history.

[sury]

David,
Aah!!! I missed the significance of the word "bounce" in your original post. Now I know why some of my
previous bounce flash experiments failed. Thank you very, very much for taking time to explain the things to
newbies likes me. Much appreciated.

With best regards,
Sury

[David Kilpatrick]

David, does your advice above about using ISO 400 also apply to the smaller HVL-F36AM flash?

Definitely, unless you feel you can use 800. With the A900, I am using 800 and stopping down to f8 for bounce shots of groups etc. f5.6 is too wide to get all the faces sharp. It helps to have a couple of extra wireless flash units in a large room. If you do the calculations: GN36 (at maximum zoom) = GN28 at standard coverage. GN28 = f2.8 at 10 metres = 33 feet. This assumed a normally decorated interior with a normal height ceiling. You can halve the distance for outdoors at night, stadiums etc. Now assume a group placed 4m from the camera, and a ceiling 2m above the flash (I realise some ceilings are only 1m above the flash, but if they are you get terrible results anyway. Distance from flash to ceiling, plus ceiling to group, is about 6m. Ceiling absorbs or scatters 50 per cent of the light (even a white ceiling will do this) so this now equals 12m. So at f2.8 with ISO 100, the shot would be about 1/2 stop underexposed. You need some leeway for auto exposure and variations in the above scenario, so setting ISO 400 is by far the safest option even on Program flash which will select apertures around f2.8 to f4. At f5.6 you are right on the edge again.

Chances are that some available light, and better conditions than those mentioned, will make most domestic bounce flash shots work well at ISO 400 and f5.6 but if you want to use ISO 100, you will need f2.8.

David

[Vidgamer]

With this new external flash unit, I find that I have to do a bit of learning and experimenting to get the hang of it....

I just looked at a few holiday photos, where I used a HVL-F42 flash with my A100, and using Program mode, it often chose F4 at ISO 200 with an f2.8 lens. Not sure why it did not go wider, but it seemed stuck at f4. Switching to manual, I tried both wider and narrower apertures. Going wider, the DOF is too shallow, so it's a good thing it didn't do so in P mode!

I used manual mode for many shots @ 5.6, which did seem to work well.

Interestingly, I switched back to P mode at some point, and with an f4.0 lens, the camera selected 5.6! Does it automatically attempt go down a stop? Neat.

(What a great camera! I hope you-know-who isn't reading this! )

[bonneville]

David, .... Thank you very, very much for taking time to explain the things to
newbies likes me. Much appreciated. Sury

It's what makes this forum that extra bit special, and personal

Brian

[sury]

Brian,
Indeed and I couldn't agree more. What made me feel comfortable asking questions is the fact that
there is no condescension on the part of members providing answers and an implied eagerness
to help you get better at photography.
In the last two weeks of my participation, there are at least half a dozen kind folks who took time
to explain things, suggest links to read, shared their own experiences etc., that I learned quite a
lot in the last two weeks about my camera(s)/lenses in particular and photography in general.

With best regards,
Sury

[bakubo]

David, thanks for that great info! I will make a note of it.

[youpii]

For flash indoor portraits, I usually use the M mode. Choose a speed around 1/15s & 1/30s. ISO400/800. Aperture depends on the lens and the subject.
Using ISO400/800 & slow speed allows to "bring back" some background lights. At ISO100, you usually get a bright person and a dark background (which might be what you want).

[Alain]

For flash indoor portraits, I usually use the M mode. Choose a speed around 1/15s & 1/30s. ISO400/800. Aperture depends on the lens and the subject.
Using ISO400/800 & slow speed allows to "bring back" some background lights. At ISO100, you usually get a bright person and a dark background (which might be what you want).

If you do this : Don't forget to gel you're flash with the filter, CTO for tungsten lights. And set you're WB to tungsten.

[sury]

Why 1/15s? Isn't that slow and cause blur?

With best regards,
Sury

For flash indoor portraits, I usually use the M mode. Choose a speed around 1/15s & 1/30s. ISO400/800. Aperture depends on the lens and the subject.
Using ISO400/800 & slow speed allows to "bring back" some background lights. At ISO100, you usually get a bright person and a dark background (which might be what you want).

[sury]

Alain,
Why set WB to Tungsten? Would you explain what is a CTO filter (for tunsten lights)?

With best regards,
Sury

For flash indoor portraits, I usually use the M mode. Choose a speed around 1/15s & 1/30s. ISO400/800. Aperture depends on the lens and the subject.
Using ISO400/800 & slow speed allows to "bring back" some background lights. At ISO100, you usually get a bright person and a dark background (which might be what you want).

If you do this : Don't forget to gel you're flash with the filter, CTO for tungsten lights. And set you're WB to tungsten.