Looking at high ISO photography with the Canon 7D
The EOS 7D ISO settings go up to 12800, although it should be noted that the 12800 or ‘H’ setting needs enabling in the custom settings.
I’ve looked at aspects of high ISO noise earlier and decided that 6400 ISO should be capable of some interesting results in normal city lighting.
All the shots below were taken hand-held with a 14mm 2.8L II lens on the camera. Mostly in Av mode at f/4 which gives reasonable DOF with this lens. From previous night time shooting experience, I selected a -2/3 stop under exposure to stop light sources from burning out too much.
The -2/3EV adjustment means I’m effectively shooting at 10,000 ISO – something I could only imagine when I used to go out with my Olympus OM2 and 50/1.2 , back in film days.
Of course, if I wanted top quality images I’d be shooting at 100 ISO and with a good solid tripod – but not this time ;-)
I’ll start off with some observations about this shot of a bus shelter.
The image above has had a degree of recovery applied (to dampen down the highlights) and I’ve tweaked CA correction and Noise Reduction settings.
More problematic is the combination of fluorescent lighting in the shelter and sodium street lighting in the road. The camera’s suggested readings were good, but a bit too yellow. For shots like this I trust to my judgement and a good calibrated monitor. If I’d needed any areas of more accurate colour, I might have got my colorchecker passport out, but this is just a few shots on a walk round near where I live…
I also tried using Canon’s DPP RAW software and with a bit of tweaking it produced an image quite similar.
Different conversion software can have quite an effect on high ISO images like this. I like to have several options to choose from if need be.
The example below shows an example of Noise reduction in Canon’s DPP software (the image is at 100% in this screen grab)
Noise reduction settings are very much a question of taste and what you want to use the image for.
I do use DPP every so often, but from a usability point of view, the RAW conversion features are just a bit clunky for my tastes.
The 100% crop below shows the sort of detail that’s present in the image.
Not far away is the old church of St Mary de Castro.
It’s floodlit, but there was a service being held and I noticed the window, near the 12th century doorway (bottom rh corner)
This is the sort of shot I’d normally think of using a shift lens with, but with a bit of photoshop correction, gives an interesting view of the window. Hand held, resting on a railing, 1/8 second f/4
The picture below is a crop of the one above.
Not far away is the new Business and Law building at De Montfort University – definitely one I’ll have to return to with shift lenses , the 1Ds3 and a tripod.
Looking back from here is a much older space.
Black and white conversion needs some care at higher ISO settings.
I’ve moved the tint of the raw conversion to the green, to enhance the amount of green channel information in the picture, whilst lowering the contributions from the noisier red and blue channels. Just remember that to create a good B/W image you do not need a perfect colour one to start with. I always do my RAW conversion thinking of what I want the B/W image to look like – not the colour one I see on the screen.
This was the version I converted to B/W
The important bit to look at when adjusting the colour temperature sliders, is the histogram. Look at how noise in the different channels appears more prominently as you adjust things. Combine this with other adjustments (recovery, fill, black level) to get an image that will produce your best B/W version. As ever you -will- need to experiment with this ;-)
High ISO work?
A good camera, given the tiny pixels that have been crammed in. I’d be quite happy using this with any of Canon’s fast primes for night time work. The viewfinder is nice and bright, and the quick settings of the camera are easy to use after you’ve goot the feel for where the buttons are.
Exposure was accurate, particularly with some under exposure to reduce burning out of lighting. I don’t take this adjustment as a problem – it’s based on what I like lights to look like in night time shots.
AF worked fine in these lighting conditions, although out of habit I’ll invariably focus on a brighter more contrasty part of the scene and recompose.
Perhaps because my first AF DSLR was my old 1Ds, I’m not expecting AF to lock onto low contrast areas in near darkness. I still use distance scales and an understanding of DOF to supplement AF if I feel it’s warranted – others may want the camera to relieve them of more of this mental effort…
Now I’ve tried the 7D I’m looking forward to seeing what the 1D mark 4 is like in low light (27MP FF equivalent pixels vs. 45MP for the 7D), not to mention whatever follows my 1Ds3 next year ;-)
Note added about shooting rates in response to comment below.
Switching on high speed shooting is just something I’d not normally think of doing at night, so I just stepped out to the street (10pm here) and tried taking bursts of photos (AF off) at 12,800 ISO. At 1/100 second and faster the shutter seemed to fire at high speed. It felt slower at 1/50 and slower still at 1/30. By 1/25 it had easily halved the rate.
This didn’t change with changes in NR settings, but AF switched on at lower light levels did seem to slow the rate slightly – but only by delaying the first shot or two
Given the time needed to move the mirror and check metering I was not surprised by this. There was no real difference when switched from Av to M, so I suspect it is a combination of shutter/mirror re-cocking that in conjunction with shutter speed is causing a slowdown. Never having tried such an experiment on a 1D, I’ve no real data to compare things to.
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