A55 noise temperature dependence

[agorabasta]

Tried a quick check for the dependence of a55 noise on the sensor temperature. I thought it's very important since other cameras like a700 and especially the Nex could become unacceptably noisy at ambient temps around +30C even at moderate ISO values. The Nex in particular could become close to unusable at ISO1600 under such conditions after some 20 min of normal use due to camera/sensor heat-up.

So far, the a55 seems to be very much better. I did a few test shots at ambient temp about +25C having the cam just switched on cold, then had it do a 9 min video clip till it claimed overheating, then switched it off/on immediately and took a few more test shots.
I saw essentially no difference in noise. All that is clearly visible is some increase of purple colouring in the shadows. The intensity of that purple veiling seems to be consistent with the internal IR background from the sensor/camera heat build-up.

Below are the 100% crops of a neutral grey/black area shot at ISO1600 and pushed by +4EV in Lr3, the WB was on tungsten. The 'Detail' module was switched off completely - no NR/sharpening.

[alphaomega]

That is encouraging information although typically it does not get all that hot here in Scotland. The NEX-5 should do better than A55 if the latter has SSS switched on doing video. Also one would have thought that the metal body of NEX-5 should help with dissipating heat. Maybe not grasping the camera tight with the palm (at 37.5C) might help reducing heat build-up. Just a thought.

[agorabasta]

The Nex5, metal-bodied, does about two full stops worse than that upon heat-up.

[mike2008]

Surprising results.

What do all the naysayers going on about the ill effects of heating on the camera make of this, I wonder?