Dear all,
I recently switched from Canon 6D astro-mod to Sony A7III (also astro-mod by irrecams.de). The main reason for the system change was the lenses. Sony FE 20 G is IMHO the best lens for the Milky Way. I made a few shots from a tripod and stacked them - the results are fantastic. A7III is significantly better in terms of noise than the old Canon. However, if I use a tracker and stack 20 - 30 shots, each 30 seconds, I get an ugly circular pattern, which cannot be corrected by bias/flats/darks. Not even GraXpert can correct it.
The issue is well described here https://www.markshelley.co.uk/Astronomy/sony_coloured_polygons.html
It seems to be related only to the lenses recognized by the A7III camera. Manual lenses work fine. But this completely ruins the purpose of a low-light camera combined with a fast, sharp Sony lens.
I tried lens corrections off, and on - both are the same.
I have the latest firmware 4.01 and most probably this is the final one because it hasn't been updated since 2021.
The big question is: has Sony A7IV the same issue, or has it been resolved? There is no point of buying a new camera if the stack of many pictures yields in uncorrectable image.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
|
One hack I used when cameras were messing up with the image was to turn them off just before finishing the exposure. You might also investigate of there is any hack of the firmware to address the issue, as for Nikons there are aplenty.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
|
Since you’re shooting with the cam in manual mode, maybe tape off the contacts so that the camera has no idea what lens it is? That should prevent the lens correction artifacts if it really is lens correction artifacts.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
|
Turn off distortion correction in your menu and turn off ALL aids. I had this issue and its simply from the IBIS, and other automated systems.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
|
Thanks V.M, I switched the distortion correction, but it didn't help. IBIS was on, so I will give it a try.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Sean Mc:
Since you’re shooting with the cam in manual mode, maybe tape off the contacts so that the camera has no idea what lens it is? That should prevent the lens correction artifacts if it really is lens correction artifacts.
Then I will not be able to focus, because Sony 20 FE doesn't have a manual focus.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
I managed to take a few tracked pictures (on 2.4.2024 - no Moon), specifically 30x30s, A7III astromod, Sony FE 20 mm G @f2.5 calibrated by 20 bias, 20 flats, and 20 darks. Everything was switched off: lens corrections, stabilization, etc.. My backyard is light polluted, so there was a gradient, which was corrected by GraXpert, then stretched. Otherwise, no other corrections were applied. There are some horizontal dark bands, but this could be caused by light pollution, clouds or so, The ring disappeared, so the mystery was solved. The camera is a keeper.
 |
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
|
The Sony a7 III is absolutely amazing in night photography!
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Jakub Korbel:
I managed to take a few tracked pictures (on 2.4.2024 - no Moon), specifically 30x30s, A7III astromod, Sony FE 20 mm G @f2.5 calibrated by 20 bias, 20 flats, and 20 darks. Everything was switched off: lens corrections, stabilization, etc.. My backyard is light polluted, so there was a gradient, which was corrected by GraXpert, then stretched. Otherwise, no other corrections were applied. There are some horizontal dark bands, but this could be caused by light pollution, clouds or so, The ring disappeared, so the mystery was solved. The camera is a keeper.
Is the electronic curtain on or off? Leaving it on, it may cause some linear banding (caused by artificial light sources). Also check if the bias frames are done correctly. Check stacked image with and without bias.
Im also a proud owner of a modified A7III, it's a beast!
One cool feature: the A7 III is capable of doing full electronic exposures up to 30 seconds. If there are no light sources it is a nice feature, because it is silent and there is no shutter wear  |
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Armin Lukas:
Jakub Korbel:
I managed to take a few tracked pictures (on 2.4.2024 - no Moon), specifically 30x30s, A7III astromod, Sony FE 20 mm G @f2.5 calibrated by 20 bias, 20 flats, and 20 darks. Everything was switched off: lens corrections, stabilization, etc.. My backyard is light polluted, so there was a gradient, which was corrected by GraXpert, then stretched. Otherwise, no other corrections were applied. There are some horizontal dark bands, but this could be caused by light pollution, clouds or so, The ring disappeared, so the mystery was solved. The camera is a keeper.
Is the electronic curtain on or off? Leaving it on, it may cause some linear banding (caused by artificial light sources). Also check if the bias frames are done correctly. Check stacked image with and without bias.
Im also a proud owner of a modified A7III, it's a beast!
One cool feature: the A7 III is capable of doing full electronic exposures up to 30 seconds. If there are no light sources it is a nice feature, because it is silent and there is no shutter wear
Hi Armin, I used the built-in intervalometer and Silent shoot. in Intvl. On. It's completely silent when taking photos, I really like this feature. The darks were taken in the same way, but the flats and bias (darks for flats) were taken by normal shooting. Thanks for pointing this out. I will review the corrected flats. On the other hand, I tried also another lens Sigma 40 EF with an adapter and these bands were not at the same spot, but shifted a lot downwards. I used the same darks and bias, but flats were obviously taken for this lens and shutter setting.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Jakub Korbel:
Armin Lukas:
Jakub Korbel:
I managed to take a few tracked pictures (on 2.4.2024 - no Moon), specifically 30x30s, A7III astromod, Sony FE 20 mm G @f2.5 calibrated by 20 bias, 20 flats, and 20 darks. Everything was switched off: lens corrections, stabilization, etc.. My backyard is light polluted, so there was a gradient, which was corrected by GraXpert, then stretched. Otherwise, no other corrections were applied. There are some horizontal dark bands, but this could be caused by light pollution, clouds or so, The ring disappeared, so the mystery was solved. The camera is a keeper.
Is the electronic curtain on or off? Leaving it on, it may cause some linear banding (caused by artificial light sources). Also check if the bias frames are done correctly. Check stacked image with and without bias.
Im also a proud owner of a modified A7III, it's a beast!
One cool feature: the A7 III is capable of doing full electronic exposures up to 30 seconds. If there are no light sources it is a nice feature, because it is silent and there is no shutter wear
Hi Armin, I used the built-in intervalometer and Silent shoot. in Intvl. On. It's completely silent when taking photos, I really like this feature. The darks were taken in the same way, but the flats and bias (darks for flats) were taken by normal shooting. Thanks for pointing this out. I will review the corrected flats. On the other hand, I tried also another lens Sigma 40 EF with an adapter and these bands were not at the same spot, but shifted a lot downwards. I used the same darks and bias, but flats were obviously taken for this lens and shutter setting.
Would be interesting to see the result! Then turn on silent shutter and do all calibration frames and see if that works.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
I found the same circular bands in my pictures of comet Pons-Brooks with an A7R III.
If I understand correctly one should turn on silent shutter to prevent them?
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Jakub Korbel:
I managed to take a few tracked pictures (on 2.4.2024 - no Moon), specifically 30x30s, A7III astromod, Sony FE 20 mm G @f2.5 calibrated by 20 bias, 20 flats, and 20 darks. Everything was switched off: lens corrections, stabilization, etc.. My backyard is light polluted, so there was a gradient, which was corrected by GraXpert, then stretched. Otherwise, no other corrections were applied. There are some horizontal dark bands, but this could be caused by light pollution, clouds or so, The ring disappeared, so the mystery was solved. The camera is a keeper.
With the A7III I recommend 50 bias, 50 Darks, and 20 flats. The darks and bias can be reused.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
Federico Lorenzo Barra:
I found the same circular bands in my pictures of comet Pons-Brooks with an A7R III.
If I understand correctly one should turn on silent shutter to prevent them?
Turn off stabilization and auto correction in the settings.
The silent shutter may cause artifacts if there are artificial light sources nearby.
|
You cannot like this item. Reason: "ANONYMOUS".
You cannot remove your like from this item.
Editing a post is only allowed within 24 hours after creating it.
You cannot Like this post because the topic is closed.
0.00
7.90
2.11
0.00
0.00
0.00
