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Author Topic: A900 Update  (Read 32987 times)
BernardLanguillier
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« Reply #120 on: October 14, 2008, 04:43:26 AM »
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Quote from: Tony Beach
More like never; MLU is required to achieve absolute acuity at anything below about 1/250.  It might be sharp enough for some, but I wonder how many of those 24 million pixels are being thrown away by shoddy technique considering that even at a mere 12 million pixels I see a noticeable loss of detail between using MLU and not using it at slower shutter speeds.

This depends on the camera (and on the hand also - although I don't think that I am very steady at all). I have tack sharp hand held shots from my Mamiya ZD that were taken at much slower shutter speeds... and the camera doesn't have an AA filter to hide some imperfections.

Cheers,
Bernard
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BernardLanguillier
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« Reply #121 on: October 14, 2008, 04:49:58 AM »
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Quote from: Ray
I've tried taking photos from the back of a moving elephant and I can assure you that IS doesn't help at all. The best one can do is try and take the shots during periods of minimum movement between one lurch and the next, using the highest ISO one's camera is capable of, consistent with acceptable quality.

I've tried taking shots at 1/13th sec with my Canon 24-105 IS at 24mm. It's difficult to get a sharp image. Pretty much hit and miss at that shutter speed. Maybe the A900 would do a better job at such slow shutter speeds, but generally, any subject that's suitable for such a slow shutter speed must be very static. Not much use for street photography without flash. In fact, they are the sorts of subjects that would mostly lend themselves well to the slow and methodical procedure of setting up a tripod.

Ray,

Yes, there are certainly situations where even IS doesn't help. Still, I'd rather have it for all the real life situations listed above where it does help.

If most of your shooting is done from the top of elephants, which would be perfectly fine in my book, then you probably should buy a Nikon D700 with a 50 mm f1.4. The D700 and not a 5dII because of dust protection and the ability of the AF to track objects...

Cheers,
Bernard
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Tony Beach
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« Reply #122 on: October 14, 2008, 09:36:07 AM »
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Quote from: BernardLanguillier
This depends on the camera (and on the hand also - although I don't think that I am very steady at all).

The hand (or even a rock steady tripod) has no bearing on mirror induced vibration.
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aaykay
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« Reply #123 on: October 14, 2008, 10:02:27 AM »
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A900 6400 ISO images from a user who also shoots with the Nikon D3 (NO noise reduction done - either in-camera or otherwise):









100% crop from the above:





100% crop from the above:



The above were from the below post on dpr:

http://forums.dpreview.com/forums/read.asp...essage=29688195
« Last Edit: October 14, 2008, 10:13:03 AM by aaykay » Logged
douglasf13
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« Reply #124 on: October 14, 2008, 11:42:11 AM »
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looks good to me.
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Ray
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« Reply #125 on: October 14, 2008, 07:06:15 PM »
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Looks good to me also, considering it's ISO 6400. These are also fine examples of how noise at 100% enlargement might be quite obvious, but on a small print can be hardly noticeable. This is a factor which must be taken into consideration when comparing noise in images from different cameras with a substantially different pixel count, such as the D700 and A900, or the D3 and 1Ds3.

Unfortunately, such examples in isolation have limited usefulness. We need a comparison, not necessarily with another camera, but at least with the same camera used at ISO 1600, 800 and 400 on the identical scene so we can get an idea of just how much those images have been degraded as a result of using ISO 6400.

We should also bear in mind that high ISO images can often look impressive (for the setting) when a full ETTR is applied to a low contrast scene such as the typical indoors scene.
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BernardLanguillier
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« Reply #126 on: October 14, 2008, 07:16:36 PM »
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Quote from: Tony Beach
The hand (or even a rock steady tripod) has no bearing on mirror induced vibration.

Correct, but the mirror damping does.

Cheers,
Bernard
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aaykay
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« Reply #127 on: October 14, 2008, 09:30:50 PM »
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Quote from: Ray
Looks good to me also, considering it's ISO 6400. These are also fine examples of how noise at 100% enlargement might be quite obvious......

Especially, when absolutely NO noise reduction was done, either in-camera or in post, with a deliberate intent to show the pictures at ISO 6400, warts and all.  

Most pictures on the net, on the other hand, would have already had a couple of NR runs done on them, before being posted.
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Ray
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« Reply #128 on: October 14, 2008, 10:39:56 PM »
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Quote from: BernardLanguillier
Correct, but the mirror damping does.

Cheers,
Bernard

Bernard,
I wonder if this is actually correct, that the hand has no bearing on mirror induced vibration. I would have thought that grasping a camera firmly with both hands would provided additional dampening of mirror slap.

It shouldn't be too difficult to test. Mirror slap tends to have its greatest effect on image sharpness at shutter speeds around 1/30th, on a tripod. Having confirmed that this is the case, with a particular camera and lens, one could then take a few shots at 1/30th, hand-held using IS on the same lens, and check the difference. One would want to choose a focal length such that 1/30th, hand-held with IS should be sufficient for a sharp image, for example 24mm.
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Tony Beach
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« Reply #129 on: October 14, 2008, 10:48:38 PM »
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Quote from: BernardLanguillier
Correct, but the mirror damping does.

There are a lot of issues that contribute to how deleterious mirror vibration will be (or not be), and we don't know how much mirror dampening the A900 can accomplish, but IS will not stop the camera from recording the likely significant mirror vibration.  Since you mentioned the Mamiya ZD, it should be noted that camera weighs about 5 pounds with its back attached, and that kind of weight contributes to the dampening of mirror vibration; and the photosites are considerably larger than the A900 photosites, which also minimizes the recording of mirror vibration.  The bottom line is that the A900 weighs 2.5x less than the ZD and its photosites are half as large.
« Last Edit: October 14, 2008, 10:52:31 PM by Tony Beach » Logged
BernardLanguillier
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« Reply #130 on: October 15, 2008, 05:56:28 AM »
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Quote from: Tony Beach
There are a lot of issues that contribute to how deleterious mirror vibration will be (or not be), and we don't know how much mirror dampening the A900 can accomplish, but IS will not stop the camera from recording the likely significant mirror vibration.  Since you mentioned the Mamiya ZD, it should be noted that camera weighs about 5 pounds with its back attached, and that kind of weight contributes to the dampening of mirror vibration; and the photosites are considerably larger than the A900 photosites, which also minimizes the recording of mirror vibration.  The bottom line is that the A900 weighs 2.5x less than the ZD and its photosites are half as large.

Agreed on the principle, but I am talking about the ZD camera, not the 645 AFII + ZD back, the weight is closer to 3 pounds. Similar to that of a 1ds3 or D3 in fact, eventhough the camera is more bulky.

It is true that it is heavier with larger pixels, but on the other hand the mirror is much larger also and has to travel more which should worsen the situation.

Anyway, it is true that IS will not get rid of mirror vibration on the A900, but this does IMHO not reduce the value of IS. A tripod will always be a better option, but for these cases where a tripod is not an option, IS on wide will be very valuable.

Cheers,
Bernard
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BernardLanguillier
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« Reply #131 on: October 15, 2008, 07:02:13 AM »
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Don't know if this has been posted in this thread already, but Raw Developper 1.8.1 now supports the A900.

Considering that it is the best demoisaicing engine out there, I would think that comparisons should best be done from RD conversions.

Cheers,
Bernard
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ErikKaffehr
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« Reply #132 on: October 15, 2008, 01:14:09 PM »
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Well,

It is a larger mirror. Focal plane shutters do also cause vibration. On the Pentax 67 shutter vibration was worse then vibration fro the mirror. Why do you think that IS does not compensate for vibration from mirror?

Best regards
Erik

Quote from: BernardLanguillier
Agreed on the principle, but I am talking about the ZD camera, not the 645 AFII + ZD back, the weight is closer to 3 pounds. Similar to that of a 1ds3 or D3 in fact, eventhough the camera is more bulky.

It is true that it is heavier with larger pixels, but on the other hand the mirror is much larger also and has to travel more which should worsen the situation.

Anyway, it is true that IS will not get rid of mirror vibration on the A900, but this does IMHO not reduce the value of IS. A tripod will always be a better option, but for these cases where a tripod is not an option, IS on wide will be very valuable.

Cheers,
Bernard
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BernardLanguillier
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« Reply #133 on: October 15, 2008, 06:20:43 PM »
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Quote from: ErikKaffehr
It is a larger mirror. Focal plane shutters do also cause vibration. On the Pentax 67 shutter vibration was worse then vibration fro the mirror. Why do you think that IS does not compensate for vibration from mirror?

Just guessing, but my underdtanding is that IS typically works best on regular vibrations. It would probably have a harder time compensating for a very fast one shot event like a mirror movement.

Cheers,
Bernard
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Ray
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« Reply #134 on: October 15, 2008, 07:23:36 PM »
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Quote from: ErikKaffehr
Well,

It is a larger mirror. Focal plane shutters do also cause vibration. On the Pentax 67 shutter vibration was worse then vibration fro the mirror. Why do you think that IS does not compensate for vibration from mirror?

Best regards
Erik

The effects of mirror vibration when using IS for hand-held shots is an interesting subject worthy of some careful testing.  It certainly seems reasonable to suppose that the floating element in an IS lens is not able to react quickly enough to counter the relatively high frequency vibration of mirror slap, and probably the same for the anti-shake sensor.

However, the question is, do the conditions of holding a camera firmly with both hands and pressing it against one's cheek, have the effect of providing additional dampening of mirror slap so that it ceases to be a problem (or at least becomes less of a problem)? Without having done specific testing of this issue, my guess would be a yes.

If the answer is 'no', then that has serious implications for the value of IS in wide angle lenses. It would partly explain why Canon has not provided IS in a number of its wide angle primes and zooms , and it would suggest that the claimed additional benefit of the anti-shake sensor in the A900, in respect of these wide angle lenses which sometimes don't have IS in the Canon equivalent, is misleading.

My own tests have confirmed that the effects of mirror vibration when camera is on a tripod are most pronounced around 1/30th of a second. They get gradually less as one moves away from that shutter speed, in either direction, so by 1/60th and 1/15th exposure, loss of sharpness due to mirror slap is (or can be) insignificant.

Now it's clear that this range of shutter speeds, 1/15th to 1/60th, is the range which is most likely to be used with wide angle lenses in poor light. It's the range which, without the benefits of IS, one could not expect tack sharp results.

So basically we're caught between a rock and a hard place. If lighting is good so we can use a shutter speed faster than 1/60th, we don't need IS (with wide angle lenses). If lighting is poor and requires a shutter speed between 1/15th and 1/60th, IS won't help much because of mirror slap. If lighting is so poor that a shutter speed slower than 1/15th is required (1/10th & 1/6th sec etc), then IS will help, but you really can't expect a truly sharp image at such slow speeds, although one might get results acceptably sharp for small prints.

Edit: Some more thoughts on this issue. The Live View feature on Canon's latest DSLRs gets around this problem nicely. If it's true that mirror vibration is not sufficiently dampened when camera is hand-held at shutter speeds from 1/15th to 1/60th, then using Live View solves the problem. The mirror is up and the view is stabilised if the lens has IS. With Live View in all its latest cameras, there is now a good reason for Canon to provide IS in all its wide angle lenses. In this context, the lack of a Live View in the A900 can be seen as a major disadvantage (unless it's true that pressing a camera to one's cheek dampens mirror vibration).
« Last Edit: October 15, 2008, 07:45:05 PM by Ray » Logged
BernardLanguillier
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« Reply #135 on: October 15, 2008, 08:03:37 PM »
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Quote from: Ray
My own tests have confirmed that the effects of mirror vibration when camera is on a tripod are most pronounced around 1/30th of a second. They get gradually less as one moves away from that shutter speed, in either direction, so by 1/60th and 1/15th exposure, loss of sharpness due to mirror slap is (or can be) insignificant.

How about testing the A900 first before drawing conclusion on the actual damping issue of its mirror.

Regards,
Bernard
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Ray
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« Reply #136 on: October 15, 2008, 09:13:26 PM »
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Quote from: BernardLanguillier
How about testing the A900 first before drawing conclusion on the actual damping issue of its mirror.

Regards,
Bernard

I'm drawing inferences, not conclusions. Until testing and comparisons are made along the lines I've suggested, no firm conclusions can be made. If someone wishes to make a point that mirror dampening in the A900 is a major improvement on other FF 35mm DSLRs, such as the 5D which I know from my own testing is very susceptible to mirror vibration at 1/30th sec exposure, then let them show the results of their tests with camera on tripod, with and without MLU enabled.
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ErikKaffehr
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« Reply #137 on: October 16, 2008, 12:58:53 AM »
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Hi,

Without formal testing I can say that AS works for wide angles on Sony Alpha (A100 and A700) and also on the KM7D, which I all had. I actually think that minor slap causes very little vibrations on those cameras, possibly with exception to the Alpha 100, from what I have see. I did not do consistent tests with resolution test targets. It's more experience from taking 30 k pictures.

I have done some tests, shooting star tracks from tripod using long telephoto (400 + 1.4X) and I could not really see difference with or without mirror lockup, but that was obviously with long exposure times.

Erik




Quote from: Ray
The effects of mirror vibration when using IS for hand-held shots is an interesting subject worthy of some careful testing.  It certainly seems reasonable to suppose that the floating element in an IS lens is not able to react quickly enough to counter the relatively high frequency vibration of mirror slap, and probably the same for the anti-shake sensor.

However, the question is, do the conditions of holding a camera firmly with both hands and pressing it against one's cheek, have the effect of providing additional dampening of mirror slap so that it ceases to be a problem (or at least becomes less of a problem)? Without having done specific testing of this issue, my guess would be a yes.

If the answer is 'no', then that has serious implications for the value of IS in wide angle lenses. It would partly explain why Canon has not provided IS in a number of its wide angle primes and zooms , and it would suggest that the claimed additional benefit of the anti-shake sensor in the A900, in respect of these wide angle lenses which sometimes don't have IS in the Canon equivalent, is misleading.

My own tests have confirmed that the effects of mirror vibration when camera is on a tripod are most pronounced around 1/30th of a second. They get gradually less as one moves away from that shutter speed, in either direction, so by 1/60th and 1/15th exposure, loss of sharpness due to mirror slap is (or can be) insignificant.

Now it's clear that this range of shutter speeds, 1/15th to 1/60th, is the range which is most likely to be used with wide angle lenses in poor light. It's the range which, without the benefits of IS, one could not expect tack sharp results.

So basically we're caught between a rock and a hard place. If lighting is good so we can use a shutter speed faster than 1/60th, we don't need IS (with wide angle lenses). If lighting is poor and requires a shutter speed between 1/15th and 1/60th, IS won't help much because of mirror slap. If lighting is so poor that a shutter speed slower than 1/15th is required (1/10th & 1/6th sec etc), then IS will help, but you really can't expect a truly sharp image at such slow speeds, although one might get results acceptably sharp for small prints.

Edit: Some more thoughts on this issue. The Live View feature on Canon's latest DSLRs gets around this problem nicely. If it's true that mirror vibration is not sufficiently dampened when camera is hand-held at shutter speeds from 1/15th to 1/60th, then using Live View solves the problem. The mirror is up and the view is stabilised if the lens has IS. With Live View in all its latest cameras, there is now a good reason for Canon to provide IS in all its wide angle lenses. In this context, the lack of a Live View in the A900 can be seen as a major disadvantage (unless it's true that pressing a camera to one's cheek dampens mirror vibration).
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ErikKaffehr
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« Reply #138 on: October 16, 2008, 01:05:35 AM »
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Hi,

I can get tack sharp pictures hand held on all cameras with wide angles at around 1/10 or even 1/4 with AS..

Erik

Quote from: Ray
The effects of mirror vibration when using IS for hand-held shots is an interesting subject worthy of some careful testing.  It certainly seems reasonable to suppose that the floating element in an IS lens is not able to react quickly enough to counter the relatively high frequency vibration of mirror slap, and probably the same for the anti-shake sensor.

However, the question is, do the conditions of holding a camera firmly with both hands and pressing it against one's cheek, have the effect of providing additional dampening of mirror slap so that it ceases to be a problem (or at least becomes less of a problem)? Without having done specific testing of this issue, my guess would be a yes.

If the answer is 'no', then that has serious implications for the value of IS in wide angle lenses. It would partly explain why Canon has not provided IS in a number of its wide angle primes and zooms , and it would suggest that the claimed additional benefit of the anti-shake sensor in the A900, in respect of these wide angle lenses which sometimes don't have IS in the Canon equivalent, is misleading.

My own tests have confirmed that the effects of mirror vibration when camera is on a tripod are most pronounced around 1/30th of a second. They get gradually less as one moves away from that shutter speed, in either direction, so by 1/60th and 1/15th exposure, loss of sharpness due to mirror slap is (or can be) insignificant.

Now it's clear that this range of shutter speeds, 1/15th to 1/60th, is the range which is most likely to be used with wide angle lenses in poor light. It's the range which, without the benefits of IS, one could not expect tack sharp results.

So basically we're caught between a rock and a hard place. If lighting is good so we can use a shutter speed faster than 1/60th, we don't need IS (with wide angle lenses). If lighting is poor and requires a shutter speed between 1/15th and 1/60th, IS won't help much because of mirror slap. If lighting is so poor that a shutter speed slower than 1/15th is required (1/10th & 1/6th sec etc), then IS will help, but you really can't expect a truly sharp image at such slow speeds, although one might get results acceptably sharp for small prints.

Edit: Some more thoughts on this issue. The Live View feature on Canon's latest DSLRs gets around this problem nicely. If it's true that mirror vibration is not sufficiently dampened when camera is hand-held at shutter speeds from 1/15th to 1/60th, then using Live View solves the problem. The mirror is up and the view is stabilised if the lens has IS. With Live View in all its latest cameras, there is now a good reason for Canon to provide IS in all its wide angle lenses. In this context, the lack of a Live View in the A900 can be seen as a major disadvantage (unless it's true that pressing a camera to one's cheek dampens mirror vibration).
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ErikKaffehr
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« Reply #139 on: October 16, 2008, 01:09:20 AM »
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Hi!

I could never confirm any advantage of mirror lock up on any of my cameras. I use it religiously anyway. Which camera do you use?

Erik


Quote from: Tony Beach
More like never; MLU is required to achieve absolute acuity at anything below about 1/250.  It might be sharp enough for some, but I wonder how many of those 24 million pixels are being thrown away by shoddy technique considering that even at a mere 12 million pixels I see a noticeable loss of detail between using MLU and not using it at slower shutter speeds.
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