Is there an SLR with no viewfinder blackout?

Started Jan 14, 2014 | Questions
schluchtenscheisser Forum Member • Posts: 74
An old solution

An accessory optical viewfinder might help you.

http://www.griffinfilmworks.com/#!articles.tewe_viewfinder

I use it with a Panasonic G1 for series of pictures (burst).

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tenAMor

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Erik Magnuson Forum Pro • Posts: 12,247
Re: To what question?
2

Vikas Rana wrote:

Erik Magnuson wrote:

An SLT does not update the EVF during still exposures. The top-of-the-line A99 doesn't even supply live view updates at 6 FPS continuous -- just replays of the previous exposure (past not present). You don't get actual updates until you drop down to 3 FPS. Heck, even a Canon Rebel can do better flapping it's mirror at 4-5 FPS.

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Erik

I'm not sure about A99 but SLT A77 provides updates with 12 fps, like any other SLR/Ts it blacked out in long exposures

http://www.dpreview.com/reviews/sonyslta77/10

"Another disadvantage of the SLT system when it comes to fast shooting is that it isn't possible for the A77 to maintain a live view feed in its fastest 8fps and 12fps continuous capture modes. The viewfinder does not black out when shooting at these high framerates, but shows a sequence of still frames in real time. What this means is that at any given moment, you don't see the view through the camera's lens right now, but how it was a fraction of a second ago. This makes little or no difference if you're shooting slow-moving or static subjects, but it makes panning with fast-moving subjects very hard indeed, since you never know where they are - only where they were."

This is even worse than blacking out combined with real-time.

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Erik

Vikas Rana
Vikas Rana Contributing Member • Posts: 916
Re: To what question?

Erik Magnuson wrote:

Vikas Rana wrote:

Erik Magnuson wrote:

An SLT does not update the EVF during still exposures. The top-of-the-line A99 doesn't even supply live view updates at 6 FPS continuous -- just replays of the previous exposure (past not present). You don't get actual updates until you drop down to 3 FPS. Heck, even a Canon Rebel can do better flapping it's mirror at 4-5 FPS.

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Erik

I'm not sure about A99 but SLT A77 provides updates with 12 fps, like any other SLR/Ts it blacked out in long exposures

http://www.dpreview.com/reviews/sonyslta77/10

"Another disadvantage of the SLT system when it comes to fast shooting is that it isn't possible for the A77 to maintain a live view feed in its fastest 8fps and 12fps continuous capture modes. The viewfinder does not black out when shooting at these high framerates, but shows a sequence of still frames in real time. What this means is that at any given moment, you don't see the view through the camera's lens right now, but how it was a fraction of a second ago. This makes little or no difference if you're shooting slow-moving or static subjects, but it makes panning with fast-moving subjects very hard indeed, since you never know where they are - only where they were."

This is even worse than blacking out combined with real-time.

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Erik

It may be an issue in earlier firmwares and fixed later but EVF only shows what sensor sees, watch this video and see how milliseconds are changing after every click:

https://www.youtube.com/watch?v=E0oAno5MD5I

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Ontario Gone
Ontario Gone Senior Member • Posts: 4,183
Re: Is there an SLR with no viewfinder blackout?

Why don't you set the camera to continuous low burst and take as many as you need. Then stack them using cumulative in PP. This will add the exposures together and allow a constant view.

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Erik Magnuson Forum Pro • Posts: 12,247
Listen, don't just watch - 12FPS lasts for one second

Vikas Rana wrote:

It may be an issue in earlier firmwares and fixed later but EVF only shows what sensor sees, watch this video and see how milliseconds are changing after every click:

https://www.youtube.com/watch?v=E0oAno5MD5I

Are you listening to the audio? It's only running at 12FPS between ~ 6:03 and 6:04 after which it slows to slightly more than ~1FPS. (DPR says 14 frames @ 12FPS before it slows to 1.5FPS, so that's about right.)

At 12FPS, there is an image every 83ms. The video is 60FPS which means each video frame is ~17ms. Do the numbers in that critical second at 12FPS jump by ~17 each time or ~83? (Actually, I see it jump by about 100ms between updates, e.g. 245->345). At 1.5FPS you actually see numbers overwriting each other mid-update. BTW, why does it start "blacking out" when running at the slower speed? (Hint: it's the time when the shutter & sensor are resetting after exposure. The sensor is blocked by the second curtain!)

You can see the difference between the "discrete" and the "continuous" update of the ms numbers in the 8FPS video more easily.

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Erik

Mark Smith Veteran Member • Posts: 6,336
Also Canon EOS RT

If you want autofocus...

The EOS RT (real time)

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:

It may be an issue in earlier firmwares and fixed later but EVF only shows what sensor sees, watch this video and see how milliseconds are changing after every click:

https://www.youtube.com/watch?v=E0oAno5MD5I

Are you listening to the audio? It's only running at 12FPS between ~ 6:03 and 6:04 after which it slows to slightly more than ~1FPS. (DPR says 14 frames @ 12FPS before it slows to 1.5FPS, so that's about right.)

At 12FPS, there is an image every 83ms. The video is 60FPS which means each video frame is ~17ms. Do the numbers in that critical second at 12FPS jump by ~17 each time or ~83? (Actually, I see it jump by about 100ms between updates, e.g. 245->345). At 1.5FPS you actually see numbers overwriting each other mid-update. BTW, why does it start "blacking out" when running at the slower speed? (Hint: it's the time when the shutter & sensor are resetting after exposure. The sensor is blocked by the second curtain!)

You can see the difference between the "discrete" and the "continuous" update of the ms numbers in the 8FPS video more easily.

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Erik

Because of lens distortions SLT speed depends upon the lens used. I got 4fps on my A58 with kit lens but using Tamron I got 6fps, 3fps onwards.

The DPR says that the distortion does not effect the speed but in real test without distortion A77 perfoms 4fps after 12fps. SLT Reviews on DPR are either outdated or wrong.

A77 Test, 12fps in 1st sec, 4fps onwards

http://www.dpreview.com/forums/thread/3589129

A58 Test, 6fps in 1st sec, 3fps onwards

http://www.dpreview.com/forums/thread/3590401

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DaveOl
DaveOl Veteran Member • Posts: 3,191
Re: Pellicles

Vikas Rana wrote:

DaveOl wrote:

Any of the old pellicle mirror cameras, but almost all were film cameras.

Its Canon EOS RT, but it reflects 2/3 (66.66%) of light to OVF & 1/3 (33.33%) to film that results in noise as well as slower shutter speed.

SLTs sensor get 70% of light that served to EVF, only 30% goes to A/F mechanism.

But Canon EOS RT OVF does not blackout

I didn't realize that the pellicle mirrors "ate" that much light!

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peevee1 Veteran Member • Posts: 6,247
Re: To what question?

Erik Magnuson wrote:

Vikas Rana wrote:

Erik Magnuson wrote:

An SLT does not update the EVF during still exposures. The top-of-the-line A99 doesn't even supply live view updates at 6 FPS continuous -- just replays of the previous exposure (past not present). You don't get actual updates until you drop down to 3 FPS. Heck, even a Canon Rebel can do better flapping it's mirror at 4-5 FPS.

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Erik

I'm not sure about A99 but SLT A77 provides updates with 12 fps, like any other SLR/Ts it blacked out in long exposures

http://www.dpreview.com/reviews/sonyslta77/10

"Another disadvantage of the SLT system when it comes to fast shooting is that it isn't possible for the A77 to maintain a live view feed in its fastest 8fps and 12fps continuous capture modes. The viewfinder does not black out when shooting at these high framerates, but shows a sequence of still frames in real time. What this means is that at any given moment, you don't see the view through the camera's lens right now, but how it was a fraction of a second ago. This makes little or no difference if you're shooting slow-moving or static subjects, but it makes panning with fast-moving subjects very hard indeed, since you never know where they are - only where they were."

This is even worse than blacking out combined with real-time.

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Erik

No, it is not worse. I bet you have never tried it, but actually showing what you get at high frame rate allows you easily and naturally adjust camera position to catch the movement.

Erik Magnuson Forum Pro • Posts: 12,247
Re: To what question?

peevee1 wrote:

Not worse. I bet you have never tried it,

I've tried such a system.

but actually showing what you get at high frame rate allows you easily and naturally adjust camera position to catch the movement.

Perhaps with such small buffers, you don't have time to notice.  If the motion is perfectly linear, just normal anticipation and follow through will suffice for a short enough time, but adjusting to changes is difficult.

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Erik

Erik Magnuson Forum Pro • Posts: 12,247
Re: Listen, don't just watch - 12FPS lasts for one second

Vikas Rana wrote:

SLT Reviews on DPR are either outdated or wrong.

It matched the videos you cited as a reference -- which likely had lens correction on.   In those videos (dated Dec 2013), the SLTs actually have the worst of both worlds: the EVF shows the past at the highest speeds and there is still a blackout at slower speeds.

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Erik

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:

SLT Reviews on DPR are either outdated or wrong.

It matched the videos you cited as a reference -- which likely had lens correction on. In those videos (dated Dec 2013), the SLTs actually have the worst of both worlds: the EVF shows the past at the highest speeds and there is still a blackout at slower speeds.

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Erik

A77 Test, 12fps in 1st sec, 4fps onwards

http://www.dpreview.com/forums/thread/3589129

A58 Test, 6fps in 1st sec, 3fps onwards

http://www.dpreview.com/forums/thread/3590401

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Erik Magnuson Forum Pro • Posts: 12,247
Re: Listen, don't just watch - 12FPS lasts for one second

Vikas Rana wrote:

Erik Magnuson wrote:

Vikas Rana wrote:

SLT Reviews on DPR are either outdated or wrong.

It matched the videos you cited as a reference -- which likely had lens correction on. In those videos (dated Dec 2013), the SLTs actually have the worst of both worlds: the EVF shows the past at the highest speeds and there is still a blackout at slower speeds.

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Erik

A77 Test, 12fps in 1st sec, 4fps onwards

OK with lens correction off, the A77 is faster than if lens correction is on as in the video or DPR's test.   What does this have to do with EVF update/blackout?  Are you suggesting that the EVF will behave differently at 12 FPS with lens correction off?  (Not likely - there is still the shutter in the way.)  If you can find a video with different EVF results, that's relevant although the videos you referenced are only a month old.

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Erik

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:

Erik Magnuson wrote:

Vikas Rana wrote:

SLT Reviews on DPR are either outdated or wrong.

It matched the videos you cited as a reference -- which likely had lens correction on. In those videos (dated Dec 2013), the SLTs actually have the worst of both worlds: the EVF shows the past at the highest speeds and there is still a blackout at slower speeds.

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Erik

A77 Test, 12fps in 1st sec, 4fps onwards

OK with lens correction off, the A77 is faster than if lens correction is on as in the video or DPR's test. What does this have to do with EVF update/blackout? Are you suggesting that the EVF will behave differently at 12 FPS with lens correction off? (Not likely - there is still the shutter in the way.) If you can find a video with different EVF results, that's relevant although the videos you referenced are only a month old.

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Erik

I'm not saying the EVF behave differently I'm just saying that its not the past, 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... Now don't tell me that you see some lag in 12fps blackouts

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Erik Magnuson Forum Pro • Posts: 12,247
Re: Listen, don't just watch - 12FPS lasts for one second

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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Erik

Midwest Forum Pro • Posts: 17,159
BZZT! Sorry, that's incorrect...

tsk1979 wrote:

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Tanveer
My galleries - http://tanveer.smugmug.com,
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BZZZZT! I'm sorry, that answer is incorrect because a DSLR has an optical viewfinder. The SLT does not. But thank you for playing the game!

Vikas Rana
Vikas Rana Contributing Member • Posts: 916
Re: Listen, don't just watch - 12FPS lasts for one second
1

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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Erik

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: http://www.humanbenchmark.com/tests/reactiontime/

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Erik Magnuson Forum Pro • Posts: 12,247
Re: Listen, don't just watch - 12FPS lasts for one second

Vikas Rana wrote:

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

Variable width characters make ASCII art somewhat imprecise.

but the truth is OVF also shows the past because when sensors is engaged the mirror is on upward position

The OVF shows nothing for that part of the cycle - it's blacked out remember? Your eye/brain may have some persistence of vision of the last view but your eye/brain also interpolates forward. (That's how those "spinning but not spinning" optical illusions work - they trick your brain into anticipating movement that doesn't happen.)

and the view presented by an OVF is the view when the mirror was down...

And when the mirror is back down, the view updates at the speed of light - no machine-induced lag.

with SLR mirror either light with go to OVF or the sensor! think again.

Exactly - it's either black or real time but never the past.

And yes its the human brain which takes time to process the information, understand & react over it.

The brain has some wonderful interpolation/estimation capabilities to work around this for common situations. That's why we can hit fastballs, watch movies, etc.  We see the past but live in the present - ever wonder how the brain manages that trick?

The normal reaction time of a human is 250ms to 300ms..

Yep. Now add the extra 125ms of display lag to that. This makes the interpolation/estimation that much harder as it's totally unnatural.

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Erik

Lanidrac Veteran Member • Posts: 8,060
Don't make sense to me
1

PhotomuseX wrote:

Hi there, I am a professional photog looking to further a personal project involving long exposures. I would like to track my subject throughout the exposure. Currently, viewfinder blackout does not allow me to maintain visual contact with my subject as I expose for 1 second or longer.

Does anyone know of an SLR that does not have any viewfinder blackout? I would greatly appreciate any recommendations.

Thank you!

If you are shooting a long exposure pic there is no way that you should want to fuss with your camera "to track your subject" because doing so will RUIN IT!, Mr. Professional.

Its hard enough to stop mirror flop movement (requiring mirror lockup) ruining a nightime star shot ...and also reducing ground vibrations via a steady heavy tri-pod too. Messing with the camera during a SINGLE long exposure is not what you want to do unless you are taking multiple exposures.

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Lanidrac Veteran Member • Posts: 8,060
Where's the OP anyway?

Ontario Gone wrote:

Why don't you set the camera to continuous low burst and take as many as you need. Then stack them using cumulative in PP. This will add the exposures together and allow a constant view.

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Good idea, Ontario Gone. Stack 'em and rack 'em.

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