arbitrage wrote: dclark wrote:
@bclaff@@ asked that I send him electronic shutter, ES, files to supplement the mechanical shutter files he had already analysed. This was to see if there was any difference in read noise. He just sent me a note saying the ES read noise is slightly higher, but the surprise was that the dual gain transition returned to ISO 500. I think he will publish that data on his site soon.
Do we know why Bill hasn't added the ES data to the A1II list yet? I would think this would be important as most A1II shooters are going to live in ES.
Also, do we know if the A1 was ever tested in MS? Could the A1 have been ISO 640 in MS and Bill only ever tested ES and got the ISO 500 we've all come to accept as the one and only dual-gain in the A1?
Geoff,
I sent him a note a couple of days ago asking about the ES data and he replied he was busy with some other projects. I sent him the files he needs and did some testing myself to verify that the MS and ES high conversion gain (HCG) points are 640 and 500. I have no idea why they are not the same. There was one point that created some confusion. In gathering the files for his analysis, black files are gathered for read noise measurements. His instructions say black files can be gathered either my putting on the lens cap or removing the lens and putting a body cap on the camera. For some bizarre reason in ES mode the HCG is 500 with the lens attached and 640 without the lens attached. That created some confusion until I managed to figure out what was going on. The ES data will use data gathered with the lens attached.
FYI, I assume the A1 data on PhotonstoPhotos is for MS. Bill's instructions to people contributing files are detailed and he specified MS should be used. For the A1II I also sent some ES data which he took a look at and noticed the HCG difference.
It is easy for you to check the HCG point yourself. Set up your camera with the lens cap on, SS set to something high (I use 1/8000). Take a series of black frames at different ISO's (e.g. 320, 400, 500, 640, 800). Load them into LrC, boost the exposure by +5 stops, and examine noise in each frame. You can easily see the drop in noise when the HCG ISO is reached. For the A1II MS that is ISO 640, for the A1II ES that is 500. Doing the same test for the A1 shows the HCG ISO is 500 for both MS and ES.
I expect Bill will eventually post both sets of data, but given the conflicts for his time it may be a while.
Dave
Edit: Added the charts below. All taken single frame, uncompressed.
arbitrage wrote: dclark wrote:
@bclaff@@ asked that I send him electronic shutter, ES, files to supplement the mechanical shutter files he had already analysed. This was to see if there was any difference in read noise. He just sent me a note saying the ES read noise is slightly higher, but the surprise was that the dual gain transition returned to ISO 500. I think he will publish that data on his site soon.
Do we know why Bill hasn't added the ES data to the A1II list yet? I would think this would be important as most A1II shooters are going to live in ES.
Also, do we know if the A1 was ever tested in MS? Could the A1 have been ISO 640 in MS and Bill only ever tested ES and got the ISO 500 we've all come to accept as the one and only dual-gain in the A1?
Geoff,
I sent him a note a couple of days ago asking about the ES data and he replied he was busy with some other projects. I sent him the files he needs and did some testing myself to verify that the MS and ES high conversion gain (HCG) points are 640 and 500. I have no idea why they are not the same. There was one point that created some confusion. In gathering the files for his analysis, black files are gathered for read noise measurements. His instructions say black files can be gathered either my putting on the lens cap or removing the lens and putting a body cap on the camera. For some bizarre reason in ES mode the HCG is 500 with the lens attached and 640 without the lens attached. That created some confusion until I managed to figure out what was going on. The ES data will use data gathered with the lens attached.
FYI, I assume the A1 data on PhotonstoPhotos is for MS. Bill's instructions to people contributing files are detailed and he specified MS should be used. For the A1II I also sent some ES data which he took a look at and noticed the HCG difference.
It is easy for you to check the HCG point yourself. Set up your camera with the lens cap on, SS set to something high (I use 1/8000). Take a series of black frames at different ISO's (e.g. 320, 400, 500, 640, 800). Load them into LrC, boost the exposure by +5 stops, and examine noise in each frame. You can easily see the drop in noise when the HCG ISO is reached. For the A1II MS that is ISO 640, for the A1II ES that is 500. Doing the same test for the A1 shows the HCG ISO is 500 for both MS and ES.
I expect Bill will eventually post both sets of data, but given the conflicts for his time it may be a while.
arbitrage wrote: dclark wrote:
@bclaff@@ asked that I send him electronic shutter, ES, files to supplement the mechanical shutter files he had already analysed. This was to see if there was any difference in read noise. He just sent me a note saying the ES read noise is slightly higher, but the surprise was that the dual gain transition returned to ISO 500. I think he will publish that data on his site soon.
Do we know why Bill hasn't added the ES data to the A1II list yet? I would think this would be important as most A1II shooters are going to live in ES.
Also, do we know if the A1 was ever tested in MS? Could the A1 have been ISO 640 in MS and Bill only ever tested ES and got the ISO 500 we've all come to accept as the one and only dual-gain in the A1?
Geoff,
I sent him a note a couple of days ago asking about the ES data and he replied he was busy with some other projects. I sent him the files he needs and did some testing myself to verify that the MS and ES high conversion gain (HCG) points are 640 and 500. I have no idea why they are not the same. There was one point that created some confusion. In gathering the files for his analysis, black files are gathered for read noise measurements. His instructions say black files can be gathered either my putting on the lens cap or removing the lens and putting a body cap on the camera. For some bizarre reason in ES mode the HCG is 500 with the lens attached and 640 without the lens attached. That created some confusion until I managed to figure out what was going on. The ES data will use data gathered with the lens attached.
FYI, I assume the A1 data on PhotonstoPhotos is for MS. Bill's instructions to people contributing files are detailed and he specified MS should be used. For the A1II I also sent some ES data which he took a look at and noticed the HCG difference.
It is easy for you to check the HCG point yourself. Set up your camera with the lens cap on, SS set to something high (I use 1/8000). Take a series of black frames at different ISO's (e.g. 320, 400, 500, 640, 800). Load them into LrC, boost the exposure by +5 stops, and examine noise in each frame. You can easily see the drop in noise when the HCG ISO is reached. For the A1II MS that is ISO 640, for the A1II ES that is 500. Doing the same test for the A1 shows the HCG ISO is 500 for both MS and ES.
I expect Bill will eventually post both sets of data, but given the conflicts for his time it may be a while.
arbitrage wrote: dclark wrote:
@bclaff@@ asked that I send him electronic shutter, ES, files to supplement the mechanical shutter files he had already analysed. This was to see if there was any difference in read noise. He just sent me a note saying the ES read noise is slightly higher, but the surprise was that the dual gain transition returned to ISO 500. I think he will publish that data on his site soon.
Do we know why Bill hasn't added the ES data to the A1II list yet? I would think this would be important as most A1II shooters are going to live in ES.
Also, do we know if the A1 was ever tested in MS? Could the A1 have been ISO 640 in MS and Bill only ever tested ES and got the ISO 500 we've all come to accept as the one and only dual-gain in the A1?
Geoff,
I sent him a note a couple of days ago asking about the ES data and he replied he was busy with some other projects. I sent him the files he needs and did some testing myself to verify that the MS and ES high conversion gain (HCG) points are 640 and 500. I have no idea why they are not the same. There was one point that created some confusion. In gathering the files for his analysis, black files are gathered for read noise measurements. His instructions say black files can be gathered either my putting on the lens cap or removing the lens and putting a body cap on the camera. For some bizarre reason in ES mode the HCG is 500 with the lens attached and 640 without the lens attached. That created some confusion until I managed to figure out what was going on. The ES data will use data gathered with the lens attached.
FYI, I assume the A1 data on PhotonstoPhotos is for MS. Bill's instructions to people contributing files are detailed and he specified MS should be used. For the A1II I also sent some ES data which he took a look at and noticed the HCG difference.
It is easy for you to check the HCG point yourself. Set up your camera with the lens cap on, SS set to something high (I use 1/8000). Take a series of black frames at different ISO's (e.g. 320, 400, 500, 640, 800). Load them into LrC, boost the exposure by +5 stops, and examine noise in each frame. You can easily see the drop in noise when the HCG ISO is reached. For the A1II MS that is ISO 640, for the A1II ES that is 500. Doing the same test for the A1 shows the HCG ISO is 500 for both MS and ES.
I expect Bill will eventually post both sets of data, but given the conflicts for his time it may be a while.
arbitrage wrote: dclark wrote:
@bclaff@@ asked that I send him electronic shutter, ES, files to supplement the mechanical shutter files he had already analysed. This was to see if there was any difference in read noise. He just sent me a note saying the ES read noise is slightly higher, but the surprise was that the dual gain transition returned to ISO 500. I think he will publish that data on his site soon.
Do we know why Bill hasn't added the ES data to the A1II list yet? I would think this would be important as most A1II shooters are going to live in ES.
Also, do we know if the A1 was ever tested in MS? Could the A1 have been ISO 640 in MS and Bill only ever tested ES and got the ISO 500 we've all come to accept as the one and only dual-gain in the A1?
Geoff,
I sent him a note a couple of days ago asking about the ES data and he replied he was busy with some other projects. I sent him the files he needs and did some testing myself to verify that the MS and ES high conversion gain (HCG) points are 640 and 500. I have no idea why they are not the same. There was one point that created some confusion. In gathering the files for his analysis, black files are gathered for read noise measurements. His instructions say black files can be gathered either my putting on the lens cap or removing the lens and putting a body cap on the camera. For some bizarre reason in ES mode the HCG is 500 with the lens attached and 640 without the lens attached. That created some confusion until I managed to figure out what was going on. The ES data will use data gathered with the lens attached.
FYI, I assume the A1 data on PhotonstoPhotos is for MS. Bill's instructions to people contributing files are detailed and he specified MS should be used. For the A1II I also sent some ES data which he took a look at and noticed the HCG difference.
It is easy for you to check the HCG point yourself. Set up your camera with the lens cap on, SS set to something high (I use 1/8000). Take a series of black frames at different ISO's (e.g. 320, 400, 500, 640, 800). Load them into LrC, boost the exposure by +5 stops, and examine noise in each frame. You can easily see the drop in noise when the HCG ISO is reached. For the A1II MS that is ISO 640, for the A1II ES that is 500. Doing the same test for the A1 shows the HCG ISO is 500 for both MS and ES.
I expect Bill will eventually post both sets of data, but given the conflicts for his time it may be a while.
Dave
Jan 01, 2025 at 12:05 PM
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