A lot has been written in the photo press this year about the latest crop of DSLR cameras and their ability to shoot at high ISO’s in some instances to over 100,000 ASA with acceptable results.
With my change in cameras earlier this summer, here was a chance to try out these claims.
I spend quite a bit of time in various bonded warehouses in Islay ( for photographic reasons obviously ! ), these not being the brightest places to work should mean a good test for these new claims.
Today I was asked to shoot some images of Eric Forget, cellar master at Hine Cognac, the only Cognac supplier with a royal warrant to the Queen.
Hine Cognac are maturing some Cognac at Bunnahabhain Distillery as both companies are owned by the same group.
Traditionally Cognac finishes it maturing in casks near water but not normally on Islay, so this is a sort of experiment to see what difference it makes.
Anyway back to the photography, I had decided against using flash as this would have had the effect of making the background like a cave and I wanted to show various casks in the background.
Whilst I could ( and did ) use a tripod, my exposure times were still limited in time because my model still had to remain as still as possible through the exposure.
So no chance of using ISO 100 here as a reasonable amount of depth of field was also needed.
I felt that I couldn’t go for exposures of longer than 1/2 second because of subject movement and because of the DOF requirement, I didn’t want to use the lens any wider than F7.1.
With the shots being taken around 24-30mm in focal length, I could at least rely on better DOF because of focal length.
So putting this info into the camera, it became apparent that my ISO was going to be 800, so be it !
Checking the preview screen after exposure and things looked OK but then thats only a small screen and not an A3 print.
As options were limited, the rest of the shoot carried on as that.
I decided to do some hand held close ups of some poured Cognac, because these shots weren’t so crucial it was an opportunity to hike the ISO and see what happened.
So for the glass shot the ISO went to 2500 with an exposure of 1/5th, about the lowest that I am comfortable hand holding even with IS lenses. The aperture used was F5 as shallow DOF I felt was going to add to the composition.
Back home and on the big screen and the shots looked fine, but that’s still only at screen resolution.
The real proof of the pudding was going to be an A3 print, so the file with the glass was printed with the final result looking like a ISO 400 colour negative print from ten years ago or so, in other words pretty good with practically no noise at all.
One point worth remembering is that just like using high speed neg films in low light, low light digital photography requires a pretty exact exposure.
If when you open up the file in Photoshop or Bridge and you need to adjust the exposure ( up or down ) then the chances are it won’t make a large print, so take care with exposure metering.
So the high ISO claims are fairly accurate but why people need a camera that will effectively meter a situation in which you or the camera couldn’t focus is beyond me.
Sensor quality is more important than being able to expose at 100,000 ASA.