A99 shutter cycle - can owners pleae help me with a test?

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David Kilpatrick
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A99 shutter cycle - can owners pleae help me with a test?

Unread post by David Kilpatrick »

I am writing a report on the A99 and during my tests I have made and analysed audio recordings of the shutter cycle of the A99, A77 and D600. These enable me to study exact durations, release and speed of curtain travel, sound level and pitch.

I have been very unhappy with the extremely long - 1/3rd second or so - overall shutter cycle of the A99 and the brief blackout of the EVF which occurs between the 'first and second' noise peaks (exposure and shutter recocking). I've now made measurements and done comparisions with different settings, media cards and ruled out variables. The cycle is slightly faster with JPEG only recording, compared to R+J or R only but it's still got this blackout and delay.

During the test, I used the continuous shooting settings as well. I found that if you set the A99 to Lo continuous, and just make single exposures (easy enough on Lo), the shutter sound is entirely different - much shorter/faster, main duration around 1/6th second, no finder blackout before the shutter blind is recocked.

Can any A99 owners please do this: set the camera to manual focus, 1/200th, any aperture. Place on a table it will help you hear the sound. Set raw, as this gives the biggest difference. Other parameters don't seem to matter, except have review turned off of course. Fire the shutter in single frame mode, and then compare this was firing a single frame in Lo motordrive mode. Look through the EVF too, and repeat the exercise.

I need to know if you find the same difference that I have found, as it's possible my A99 is not operating correctly. Recap - the single frame fired in Lo motordrive mode should give you a 'normal' experience much like using the A77, and the single frame fired in one-shot drive mode should give you a blackout during an overall cycle almost twice the duration, if your camera behaves like mine.

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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by Dr. Harout »

21 days remain to get mine. So can't help you now. Sorry.
BTW, did you vote in the opinion polls?
For when will your review be ready. I'm eagerly waiting.
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David Kilpatrick
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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by David Kilpatrick »

My review is nearly finished, but I have hit this problem with the shutter. I've already in one review that it is louder than the Nikon D600, but in fact the Nikon records at 4dB peak volume higher than the A99 - just under half the duration of the sound of mine. My A99 has a total sound duration of between 340 and 420ms when fired. I am now being told by at least one owner that their camera does not have this problem.

So I need to solve this issue before releasing any review.

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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by agorabasta »

David Kilpatrick wrote:I've now made measurements and done comparisions with different settings, media cards and ruled out variables.
The earlier bodies all measured fastest without any card inserted.
Of the existing SD/MS format cards, the HX variety of Sony MS have the lowest latency due to their 8-bit interface (which doesn't mean the highest throughput, though).
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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by David Kilpatrick »

This recording may not seem to show a significant difference, that will be down to your ears (I have good enough ears - you need to in order to tell an accurately played fast triplet in Irish music from a random mess!).
single-versus-lo.jpg
single-versus-lo.jpg (31.05 KiB) Viewed 6660 times
http://www.photoclubalpha.com/single%20versus%20lo.mp3

The block I have marked in green on the first (single shot mode) sound corresponds to a short blackout of the EVF, which is not present in sequence shooting mode and does not appear to be necessary for proper operation. It's just disruptive. I believe it can be eliminated by a firmware fix, shortening the single shot shutter cycle from about 1/3rd of a second overall, to under 1/4. That brief 1/10th of a second blackout may not seem much but it does not have to be there.

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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by Greg Beetham »

Yep definitely different sounds, ka-click vs kaclick, it would be interesting to get a high speed video of the shutter doing each one.
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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by Dr. Harout »

OK, then a question arises: is there any difference with both situations on a same shot (that is: sound change might imply difference in shutter speed, thus influencing on the exposure).
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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by Greg Beetham »

I had gotten involved elsewhere in a discussion about the A99 and its shutter, to cut a long story short it seemed that the only answer to the problem was that the A99 has the ability to change its shutter cycle time on occasion in the 1/250sec setting, (flash sync with oem flash vs non oem flash seemed to have two different versions of 1/250sec shutter, one fully open and one not fully open) maybe it does something similar with 1/200sec as well.
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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by David Kilpatrick »

Neither. The situation was controller very carefully. There are no variables other than a difference between the way in which the A77 handles single exposures (exactly the same as it handles sequence exposures made singly), the way the A99 handles single exposures, and the way the A99 handles sequences.

There are other points of interest, for example, in any given high-speed 6fps sequence the FIRST frame involves a finder blackout, but all subsequent frames do not - they involve an update which may lag, but the finder never goes black despite image data being transferred and saved/buffered.

If the camera can do this, why on earth does it require a blackout in single frame mode? The A77 has a blackout no longer than a normal mirror-flip blackout on a regular DSLR. The A99 has an extremely long duration blackout which is disruptive. There only data difference is 14-bit versus 12-bit, and I do appreciate that this means four times the data must be moved and compressed.

If so, the penalty paid for 14-bit (not optional, no 12-bit choice) capture is extreme. And it still does not explain how sequences can be shot without the problem.

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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by Greg Beetham »

Maybe the dark frame for the rapid sequence shots is only taken at the first shot and no subsequent shots? But why there should be a difference in shutter actuation between one single shot image and shutter actuations in Lo drive sequence shots is a mystery so far. (how does an LV sensor do a dark frame anyway?)
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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by David Kilpatrick »

It's not a dark frame, just a longer period of finder blackout. The sensor is physically covered by the shutter curtain, so there will always be a blackout at this point, before the curtain is re-cocked to open position. The shutter, as the sonograms I've made prove, is motor driven not spring cocked (the motor sound happens continuously during the transit of the curtain.

During 3fps shooting there is a very strong blackout for every frame, even though the period is brief. 6fps seems to force the EVF display buffer to retain its contents until replaced, for each frame, without any period of black though of course the sensor is still being covered at the end of each exposure.

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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by Greg Beetham »

No I wasn’t offering that as an explanation, I was just wondering how an LV sensor even does a dark frame mainly, maybe it happens at the end of a shot instead? The shutter sounds I listened too are two different mechanical sounds of course and a dark frame wouldn’t cause the prolonged different shutter sound in single shot vs rapid shot mode, but the camera is doing ‘something’ differently even though the shutter speed is the same in both cases. There does seem to be a shutter cycle time difference between the two 1/200sec shutters…for reasons unknown.
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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by David Kilpatrick »

I am able to see the cycle in detail. There is a 1/10th second period after the exposure, during which the viewfinder is black and the shutter has not re-cocked, in single frame mode but not in sequence mode.

I am very surprised that on dPreview not a single person has been able to test their A99. I have no idea whether all cameras behave like this or not.

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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by Greg Beetham »

David Kilpatrick wrote:I am able to see the cycle in detail. There is a 1/10th second period after the exposure, during which the viewfinder is black and the shutter has not re-cocked, in single frame mode but not in sequence mode.

I am very surprised that on dPreview not a single person has been able to test their A99. I have no idea whether all cameras behave like this or not.

David
David I'm surprised that you're surprised, having seen first hand how well some people read and understand what they are reading and reach conclusions I'm not really surprised all that much, most seem to be heavily involved with the concern at the moment over how well the A99 does video (or not) and all else is put on the backburner...I think.
Greg

I just had a look at the thread http://forums.dpreview.com/forums/thread/3343079 and it looks like two A99 owners have reached the conclusion that their cameras don't vary between single shot and continuous shot mode...?
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Re: A99 shutter cycle - can owners pleae help me with a test

Unread post by Manfred »

First post to provide my input to the A99 shutter cycle question. There is indeed a very subtle difference in the shutter cycle sound as perceived by ear between single frame and sequence modes, in that with single frame the whole cycle seems longer, but I did not find any difference in blackout periods either way.

M
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