Why buffer slower in single mode?

[scott kirkpatrick]

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Andy, nice summary, I see the same thing. In the M9 we need to use a Sandisk Ultra II to get these speeds.

 

By my calculation, the buffer in the M9 is the same size as that in the M8. That is, 12 pix at 10mb is approx = to 7 at 18mb.

 

Gee, they listened to me when I asked for a Fast Wide Prime lens -- in face they made 2 of 'em! -- but they weren't listening with regard to the buffer.

 

And memory is so cheap.

 

Bill, the buffer in the M9 is probably 2x the size of the one in the M8, since memory prices and chip sizes move down with time at a rate that would make that step really easy. With all the early fuss about the strange card write speeds, the latest firmware writes without problems to a wider range of cards, but still at the same speed as before. This makes me think that the limitations are in the bandwidth that is designed into the image downstream processing unit. Incidentally the reason that the write speed for uncompressed files is no slower than for compressed is that to write a compressed pixel value the controller uses its value to pick an 8-bit value out of a table and writes that value to the card. Just a few extra instructions, easily pipelined.

 

Perhaps we should divide our wishlist into two parts:

 

functional enhancements for firmware 1.20:

Optional override of the manual lens entry when you have a 6-bit lens

Turn off the noise processing and let us see the true rgb data

Don't shut down the LCD just because the timeout from the last shutterpress has expired,

Etc., etc...

 

hardware enhancements for the M9.2 and upgrades to the M9, for YE2010:

512MB buffer, or a pipeline speedup

faster write interface, to cut the 4+ sec wait when the buffer is filled by 2x.

bring back the sapphire LCD cover and 2m framelines?

Variable-mag viewfinder?

Other stuff??? It has to be worth about $1K, or it won't happen.

 

scott

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[charlesphoto99]

Why is it that this topic cant be discussed with out someone saying the same thing every time. We know we can buy a Canon. I own a Canon, but that doesnt change a thing. Leica screwed up on this, and if they want to continue the tradition of producing some of the finest rangefinders ever produced for many more years to come they better not make the same mistake again in the third generation Digital M.

 

I want my grandchildren to feel the joy I do shooting with a digital M, but if Leica continues staying 3 steps behind technology, I'm afraid there is a chance that wont happen.

 

If you dont agree, that's great. Just please stop telling us to buy a Canon.

 

Hey, I agree that Leica should try and make the best camera out there. But not sure what is so wrong with the M9 that you can't continue to shoot with it for many many years to come? If it was so truly flawed we wouldn't be seeing so many threads about how can I get my hands on one.

 

Back in the days of film one would never choose to use an M6 or M7 if one needed 8fps. There was the Nikon F5 or Canon 1V for that. Why the ultra portable M9 should play exactly like the big boys is sometimes a bit beyond reason IMO. I'm no Leica apologist (really - esp when it comes to service) but I think it best to keep the argument within reach and stop worrying about the next one and enjoy the one that's now.

[charlesphoto99]

Ok, so that's you, Charles (and I say with this with total respect for you and your work): I don't have a dSLR for 1.5 fps speeds I just don't want to think about the buffer when I work with any top-end camera given the way I shoot (which is slow. I turn my Nikons down!).

 

BTW--my D3 is a newer dSLR and it's a million times louder than the M9 (in fact, it's the loudest camera I've ever owned... the R9 is positively silent next to that...course, the D3 is um, speedy )

 

I'd gladly pay extra on the off season to get a processor / buffer upgrade for speed (not necessarily size). I realize that's probably pie in the sky, but as I said in another thread, optimizing the firmware is probably still ongoing, and I would expect to see some improvements there.

 

OTH, moving uncompressed DNGs twice the size of my Nikon raw files is going to slow things down a bit regardless...But at least the M9 should be able to take advantage of fast SD cards, no?

 

Yeah, the D3 is a noisy beast (I've owned one since it came out), but not nearly as much as the original M8. I guess I was thinking of the 5D MkII which is actually pretty quiet all things considered. And yeah the whole SD card thing with the M9 is weird. If anything it would be nice if it was optimized for fast SD cards so download times to the computer would be faster. Of course that's the time when one can write on forums such as this one.

[digitalfx]

Hey, I agree that Leica should try and make the best camera out there. But not sure what is so wrong with the M9 that you can't continue to shoot with it for many many years to come? If it was so truly flawed we wouldn't be seeing so many threads about how can I get my hands on one.

 

Back in the days of film one would never choose to use an M6 or M7 if one needed 8fps. There was the Nikon F5 or Canon 1V for that. Why the ultra portable M9 should play exactly like the big boys is sometimes a bit beyond reason IMO. I'm no Leica apologist (really - esp when it comes to service) but I think it best to keep the argument within reach and stop worrying about the next one and enjoy the one that's now.

 

I wasn't clear, I didn't mean the M9 won't be usable for years to come, hell I was using a three year old M8 up until a few weeks ago.

 

What I meant was that if Leica continues to stay three steps behind technology they may not survive long enough to make an M12 or M14.

 

Th M9 is a fine camera, one that produces exceptional images for me. I love my M9, except for this one flaw.

 

BTW- this discussion has absolutely nothing to do with shooting 8fps.

I can't shoot 1fps w/o my camera being rendered useless after 8 exposures. Even my M2, which I have owned since I was 17 shoots faster.

[zlatkob]

Back in the days of film one would never choose to use an M6 or M7 if one needed 8fps. There was the Nikon F5 or Canon 1V for that. Why the ultra portable M9 should play exactly like the big boys is sometimes a bit beyond reason IMO.

 

It's not about shooting 8fps. It's about the camera being ready to shoot when you need it, even for an extended sequence of shots. Back in the film days, an ultra portable M7, M6, M4P & M4-2 could shoot 3fps for 36 frames with the motor winder, or about 1fps for 36 frames with manual advance. The M9 will shoot for 2fps for only 8 frames. That's a significant downgrade in one aspect of performance. Other full-frame cameras offer raw buffers in the range of 13 to 25 shots; in jpeg mode they can shoot until the card is full. I don't believe that's because they are bigger cameras, just that they have a bigger memory buffer.

 

For anyone buying the M9 now, the buffer isn't a dealbreaker. It's just something you accept in order to have its other benefits. However, this should fall in the category of "needs improvement" on someone's to-do list.

[charlesphoto99]

Okay, gotcha. Though you actually bring up a bigger problem which is "the ability to be ready to shoot.". I run into this all the time - press the shutter and nothing happens. More than a larger buffer I would much prefer the near instant start up of my D3. IMO it's the single biggest problem with the M8/9.

[pelagia]

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BTW, Tom. You're right, we're not addressing the question you asked. I don't think anyone is getting the same results you are. You're using a manual shutter speed, right, 1/250 or faster for your comparisons?

Howard, thanks. I have been testing in the auto mode.

 

Let me make some conclusions from the above thread.

1) 7 frames buffer is not enough for the majority.

2) In low light (high ISO) the processing time slows down considerably.

3) In single mode the "buffering" ability is even slower than in continuous mode (noticeable at high ISO).

4) We are not talking about machinegunning.

 

We need a camera to be ready for shooting at the right moment. Something should be re-arranged for the Single mode shooting. Whether it is a larger buffer, different processor, or the way the camera starts writing to the memory card, or...

 

Tom

[mjh]

Let me make some conclusions from the above thread.

The sample is way too small to justify any conclusions about what people want or need. We don’t know whether the buffer size is an issue for many owners of an M9. And it is also not generally true that the buffer was slower in single mode, nor that high ISO would make a difference.

 

It is just that the M9 has its limitations, like the 7 image buffer and the CPU throughput. It is something to keep in mind when selecting the M9 for a particular task.

[scott kirkpatrick]

...it is also not generally true that the buffer was slower in single mode, nor that high ISO would make a difference.

 

I agree that one can get as many shots into the buffer in S mode as in C mode, taking about the same length of time, but it is the case that operating at higher ISO slows the M9 down when the buffer pipeline is operating full or nearly full. Sean Reid(subscription site) in his first review of the M9 last fall listed the times he observed between shots once the buffer is full, and found that they increased gradually as he increased the ISO from 160 to 2500. For uncompressed, DNG-only shooting he found the shot to shot delay once the buffer is full was 2-3 sec at ISO 160 increasing to 3-5 sec at ISO 2500. The M9 must be doing something extra to each image at higher ISO, and it does it in increasing amounts as ISO increases above the base.

 

I have done both sorts of test (S and C at various ISOs) and see the same results.

 

scott

[mjh]

but it is the case that operating at higher ISO slows the M9 down when the buffer pipeline is operating full or nearly full. Sean Reid(subscription site) in his first review of the M9 last fall listed the times he observed between shots once the buffer is full, and found that they increased gradually as he increased the ISO from 160 to 2500. For uncompressed, DNG-only shooting he found the shot to shot delay once the buffer is full was 2-3 sec at ISO 160 increasing to 3-5 sec at ISO 2500. The M9 must be doing something extra to each image at higher ISO, and it does it in increasing amounts as ISO increases above the base.

Yes, the rate at which the camera fills the buffer is constant while the rate at which the raw data in the buffer gets processed and the space occupied by it released varies. (I had tried to explain this process in the other thread: http://www.l-camera-forum.com/leica-forum/leica-m9-forum/121907-petition-request-bigger-buffer-anyone-2.html#post1295772) So you can shoot at constant speeds in S or C mode and at any ISO setting as long as the buffer never fills up; once it does, you will have to wait for another image being processed and written to the card (which slightly depends on ISO, if only because noisier JPEGs take up more space) before you can take the next. But that’s just in the nature of the pipeline and is the same with any camera; just the buffer size and CPU speed varies between models. And as much as we would wish for a faster CPU, the CPU in the M9 won’t get any faster. It might be possible to upgrade the buffer size (one would have to ask Leica about that, and they might have to ask Jenoptik …), but even with a larger buffer the camera will still slow down once the buffer is full.

[yanidel]

The sample is way too small to justify any conclusions about what people want or need. We don’t know whether the buffer size is an issue for many owners of an M9. And it is also not generally true that the buffer was slower in single mode, nor that high ISO would make a difference.

That is correct, there might be a silent majority here that just does not care about buffer limits like me but does (did) not interfere in this thread.

So larger/faster buffer/processor ? If the upgrade helps some users with no additional cost to the others (price of the M9), then why not.

[pelagia]

Michael, I was concerned throughout this thread, why do I get in real life such different results from what you claim so firmly. Since I shoot a lot in low light situations such as receptions, concerts, exhibitions, dance performances, I constantly run into a very slow camera (in single mode). Therefore today I made some "scientific" testing. I can confirm everything you had said, there are hardly any differences with various ISO settings, with pure DNG or DNG+JPG, between C and S mode, AS LONG AS I TESTED IT IN GOOD LIGHT (sorry can not give you any EV figures). As soon as I shot in dark conditions, the speed slowed down about two-fold.

 

So I will take a freedom to give my next conclusion: the problem of slowing down is not that much the buffer size, not even the ISO setting. The problem is related to processing of low light images (whether it is noise reduction, demosaicing or whatsoever).

 

Tom

[mjh]

The problem is related to processing of low light images (whether it is noise reduction, demosaicing or whatsoever).

Yep, more noise means less throughput. One factor is obvious: Noise creates spurious high frequency detail and reduces redundancy in the image, resulting in bigger JPEG files that take longer to process and write to the card. There may be other factors such as a more aggressive (and CPU-intensive) noise reduction kicking in at higher ISO settings. But again, this only affects the post-buffer stages of the pipeline. The buffer serves to decouple the image processing pre and post buffer so the camera can still shoot at top speed as long as one doesn’t fill up the buffer. There are no statistics available but it is possible that many M9 shooters never even noticed the buffer’s limitation – you can easily fire three, four, or five shots is rapid succession (or what counts as “rapid” with the M9), then wait for your next chance to capture something interesting, incidentally giving the camera enough time for processing the shots in the interval.

[pelagia]

the camera can still shoot at top speed as long as one doesn’t fill up the buffer.

 

Michael, have you tested this theory? OK, I believe the technology you describe, but honestly, while shooting I do not care about the pieces of the pipeline. I want to shoot. However this is what I do and get: Set camera to AUTO ISO (or, say, ISO 2000). Set camera to S mode. Open aperture. Go to a dim place (how dim? eeh... like a cellar beer pub in Hamburg). Aim at a bartender and press the trigger, one frame immediately after another. Now if you get 7 frames at top speed with no waiting, I owe you a beer.

 

Tom

[mjh]

Michael, have you tested this theory?

Sure I have. And I just left the lens cap on; it doesn’t get any darker than that (the M9 selected ISO 2500 in Auto ISO mode). Still I’ve tested again under various lighting conditions and various settings, and with slower shutter speeds I have to admit you do have point: Shooting was reasonably fast at 1/125 s and above, but did slow down (plus the buffer did fill up faster) when using longer exposure times. For example, the M9 was much faster with 1/125 s and f2.8 than with 1/30 s and f5.6. There may be some early-stage noise reduction slowing things down, or maybe requiring more memory cutting down the buffer size (just a guess). Btw, the same thing happens in continuous mode, so S vs. C still doesn’t make a difference.