When I got the alpha 7II, I sent my old a7 off to Lifepixel to be converted for infrared. I had a hard time deciding what flavor of IR response to go for. A while ago, I had a D3 mofified with the near IR filter, and that was OK, but I wanted a more… [Read More]
Archives for 2015
Photo credits
Many years ago I interviewed Jack Welpott for the Center for Photographic Art Newsletter, Focus. You can find it and many other interviews here. As was my habit, I made a portrait of Jack to accompany the interview: Last week, the CPA posted the portrait on their Facebook page. There was no photo credit. At… [Read More]
Simulating Sony a7II photon transfer curves
In yesterday’s post, we saw markedly worse low-signal-level performance when the camera shutter mode is changed from single shot to continuous. We know from looking at histograms that the analog to digital converter (ADC) resolution changes from 13 to 12 bits when the shutter mode is thus changed. Is that sufficient to cause the observed… [Read More]
Does DRO in the a7II affect noise?
I’ve been asked to look at whether the Sony alpha 7 Mark II Dynamic Range Optimizer (DRO) affects noise at low ISOs. I ran a photon transfer curve with the camera set four different ways: Shutter mode single shot, DRO off Shutter mode single shot, DRO Auto Shutter mode single shot, DRO Lv 5 Shutter… [Read More]
Tripod-mounted Sony a7II IBIS performance
I’ve read on a photographic forum — maybe I should stop reading those things; they’re making a lot of work for me — that the a7II in-body image stabilization (IBIS, aka SteadyShot) improves image quality even with the camera on a tripod. Since the conventional wisdom is to turn off image stabilization when the camera… [Read More]