Is there an SLR with no viewfinder blackout?

Started Jan 14, 2014 | Questions thread
Vikas Rana
Vikas Rana Contributing Member • Posts: 916
Re: Listen, don't just watch - 12FPS lasts for one second

Erik Magnuson wrote:

Vikas Rana wrote:

I'm not saying the EVF behave differently I'm just saying that its not the past,

It is the past:

Here is the sequence using 8 FPS and no initial shutter lag (or perfect anticipatory timing) for nice round numbers. I'll make the optimistic assumption that it takes only 50ms to read/process the data -- most of this will be time for the full resolution readout (not many sensors can actually read out full 24+MP resolution at 20FPS!)

Clock: 000ms 025ms 050ms 075ms 100ms 125ms 150ms 175ms 200ms 225ms 250ms 300ms


EVF: 000ms 000ms 000ms 000ms 000ms 000ms 000ms 125ms 125ms 125ms 125ms etc.

So, for the first image the EVF freezes on the last scan, after that it's going to be behind the clock and jumping in ~125ms increments. As I said, you can clearly see the difference in how the clock numbers change in the 8FPS video.

it is what EVF is going to shoot and giving you what actually seen by the sensor, you can see there the clock is ticking milliseconds...

It's telling you what the sensor saw last but the clock keeps tickingl There is also a non-zero readout & processing time.

Now don't tell me that you see some lag in 12fps blackouts

Here is what a 8 FPS OVF would show (assuming ~100ms blackout like for a 7D). 12FPS would require a faster mirror mechanism but the idea is the same.

Clock: 000ms 025ms 050ms 075ms 100ms 125ms 150ms 175ms 200ms 225ms 250ms 300ms


OVF: 000ms black black black 100ms 125ms black black black 225ms 250ms black etc.


Whenever the OVF shows the clock, it shows the clock value at the speed of light. Realistically, you would not perceive both 100 and 125 discretely but a blur that looks like 1xx. The VF may be dark for most of the time but it always shows the real time w/o lag when it shows anything.

So the issue is which sequence is it easier for the human eye+brain to process and use for corrective tracking feedback. Obviously the blackout for the 7D at 12FPS is infinite because it can't do it at all and the A77 is certainly better. But for the 8FPS case, 7D is arguably better because any time you perceive is going to be the correct one and not a past one.

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Haha, lol that is a good one. according to you OVF can see the future :-D,

but the truth is OVF also shows the past because when sensors is engaged the mirror is on upward position and the view presented by an OVF is the view when the mirror was down... with SLR mirror either light with go to OVF or the sensor! think again.

And yes its the human brain which takes time to process the information, understand & react over it. The normal reaction time of a human is 250ms to 300ms.. You can perform a reaction time test here:

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