iso setting

[midwestdvr]

Just reviewing my old dive pics (not too many yet but hope to remedy that...soon) and I noticed that I've never shot a pic above iso 50. My a70 can be set at 50, 100, 200, and 400.

Would a higher iso improve a shot? In what conditions would you use a higher or lower iso setting? Thanks.

midwestdvr (currently dry and cold....aaaargh!)

 

[alcina]

You might try 100, but I wouldn't go higher than that. From what I have read there is a lot of noise associated with the higher ISO settings...but then again, you can always try and see what happens

I don't know where most of your diving is but here in viz from about 5m+ I use 50; I have had students try using 100 and the results are OK. If your water is very dark, bumping to 100 might give you just that extra edge you will need.

Experiment and let us know!

 

[fdog]

Shooting higher ISO, either film or digital, is just like crack cocaine...You get higher shutter speeds, smaller apertures (thus greater depth of field), shoot in heroicly low light conditions, get great stuff deeper, smaller strobes...on and on...

Of course, just like drugs, you pay for it later. With digital, it's noise...with film, it's grain. And of course, at that point, you pay for it forever.

The bad part is, you won't notice it while reviewing on the camera's LCD. It's later, when you're printing that award-winning moment, that you silently curse under your breath.

I shoot ISOs as low as I can as a matter of course. However, there's times you just need the shutter speed:
Sports (surfing, swimming, I shot U/W of water skiiers once)
Surge

Or, when you need the depth of field:
Big distance between foregound and background
Lens is at the verge of needing a diopter
Over/unders with rectilinear lens
Fast-action stuff set at hyperfocal

Or when it's just plain dark:
Late/early in the day
Heavy overcast
Deep
Low vis

Depending on the situation, I'll rachet up the ISO, but only with the greatest of reluctance. Like going to the dentist.

All the best, James

 

[midwestdvr]

Thanks for all the help. I might experiment with different iso settings on dry land first before doing it underwater. I really hate that feeling you get when you think you had a good shot and find out later it's crap.

Merry X-mas, y'all.

midwestdvr

 

[ssra30]

I always use lowest ISO setting on my Oly C5050 and Nikon D70 for lowest digital noise. As long as I can use the shutterspeed that I want and F stop that I want, just keep going up and down the strobe power and use higher ISO only as a last resource. On C5050 I certainly would try to avoid anything above ISO 100, not sure about the Canon though.

 

[The Kraken]

Yes, you can shoot a given emulsion at a higher "ISO". In the olden days when there was a very narrow selection of film speeds from which to choose, photographers would "push" the film, that is, set the ASA/ISO at a higher index in order primarily to get faster shutter speeds. The big kicker was that the difference in exposure had to be made up in the development of the emulsion so that when the photographer drop his film off at the lab he would tell them to "push" the development.

One of the down sides of "pushing" a film is the increase in the apparent grain structure of the emulsion and the loss of definition in resulting print.