New Sigma 60-600mm L Mount - First Effort

[drjonb]

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[michali]

On 5/8/2023 at 1:21 PM, drjonb said:

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Excellent! Would be interested to know your settings for this image.

[bags27]

M4-P M135 f/4 Tri-X in Pyrocat HD. The entire roll was in focus. It's not rocket science. 😀

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Edited May 9, 2023 by bags27

[drjonb]

1 hour ago, michali said:

Excellent! Would be interested to know your settings for this image.

Many thanks.  Shot through an open sash window (moon cooperated that night, day after full moon and very bright); rested the hood on the window frame.  Hand-held, at ISO 200, f9 or f10 I at 1/250sec - ‘under-exposed’ by around 1.5 to 2 stops.  Shot lots of frames on AFC, around ten at a time.  Spot focus in AF aimed at the moon’s right-side terminator.  Processed raw files in Capture One - to make groups of .tif files.  Then I stack the .tif files using Autostackert to create a finished, unsharpened  .tif file, which I then process in PS, I use Topaz to sharpen at the end.  I do this for several groups of images until I get one I like.  Hope this makes some sense.  It’s mostly luck related to the original seeing conditions whether you can get a decent result.  

[drjonb]

26 minutes ago, bags27 said:

M4-P M135 f/4 Tri-X in Pyrocat HD. The entire roll was in focus. It's not rocket science. 😀

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Tennis is definitely rocket science. 

[drjonb]

6 hours ago, drjonb said:

Many thanks.  Shot through an open sash window (moon cooperated that night, day after full moon and very bright); rested the hood on the window frame.  Hand-held, at ISO 200, f9 or f10 I at 1/250sec - ‘under-exposed’ by around 1.5 to 2 stops.  Shot lots of frames on AFC, around ten at a time.  Spot focus in AF aimed at the moon’s right-side terminator.  Processed raw files in Capture One - to make groups of .tif files.  Then I stack the .tif files using Autostackert to create a finished, unsharpened  .tif file, which I then process in PS, I use Topaz to sharpen at the end.  I do this for several groups of images until I get one I like.  Hope this makes some sense.  It’s mostly luck related to the original seeing conditions whether you can get a decent result.  

I forgot to say that the focal length was 840mm, with the 1.4x extender.

[jaapv]

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Just curious: why AFC? The moon is not really a fast moving subject. 

[drjonb]

46 minutes ago, jaapv said:

Just curious: why AFC? The moon is not really a fast moving subject. 

Because I want several images captured while hand-held, with as little movement in original position between first and last image in the sequence. The moon is moving so I keep the sequences of around ten images to one or two seconds.  Then reposition and start again, and then repeat.  Of course, I could use a tripod and my ‘star tracker’ mount, but this is a bit more faffing around and not necessary with a bright nearly full moon.  And by AFC I mean holding down shutter and getting multiple captures - I may not be using the correct term for that.

[jaapv]

Yes but we can assume that the distance of the moon will remain fairly constant  AFC is not really useful if the subject remains within the plane of focus. 

[drjonb]

11 minutes ago, jaapv said:

Yes but we can assume that the distance of the moon will remain fairly constant  AFC is not really useful if the subject remains within the plane of focus. 

The distance of the moon is constant, but atmospheric  conditions will shift the focus point, however, it is not about focus, it is about position.  When you are hand-holding, and intend to stack groups of many images later, it is important that the moon’s disc (which does not occupy anywhere near the full 35mm frame) stays as close to the same position within the frame for the many images.  Unless you are on a tripod, it is very difficult to keep the image position the same for consecutive frames. The OIS takes care of motion blur, but not shifts in position. If each image has moved too much, PS will struggle to align them which is why I do not often use PS’s Photomerge, but a dedicated astro image stacker (astro software allows for atmospheric conditions which change rapidly and will toss out images which are not of a certain ‘quality’ compared to the others).  It is akin to the built-in multiple image stacking that Leica offers - that system shifts the image half a micron in all directions and then stacks the 8 images in-camera to produce a 96MB RAW file, but will only work if the camera is absolutely still.  If the moon is within a certain margin in the 35mm frame, dedicated panorama software can also be used.  As I said, it is about position not focus.  And atmospheric conditions are the critical challenge, which is why luck is also involved.

[jaapv]

Yes, but AFC is not for lateral movement. The point about atmospheric influence is taken. In any case there is no argument about the excellent result. 

[drjonb]

5 minutes ago, jaapv said:

Yes, but AFC is not for lateral movement. The point about atmospheric influence is taken. 

I cannot follow your point.  For me, AFC is simply and only to allow me (off tripod) to press the shutter once, hold it down and get around ten frames in quick succession without me moving my position too much.  I know of no relationship between ‘AFC’ and lateral or any other kind of movement.

[jaapv]

AFC is meant for dynamic work, mainly for subjects moving to or away from the camera and sometimes tracking focus. AFS  is for more static subjects.that remain in the plane of focus. Firing a burst has little to do with it. I do focus stacking mostly on AFS or manual focus with a series of single shots. 

[drjonb]

2 minutes ago, jaapv said:

AFC is meant for dynamic work, mainly for subjects moving to or away from the camera and tracking focus. AFS  is for more static subjects.that remain in the plane of focus. 

As I said, I am probably not using the correct terms.  I simply set the camera so I get multiple frames captured for one full shutter press.  

[jaapv]

Whatever. The proof is the image 😀😀

[drjonb]

10 minutes ago, jaapv said:

AFC is meant for dynamic work, mainly for subjects moving to or away from the camera and sometimes tracking focus. AFS  is for more static subjects.that remain in the plane of focus. Firing a burst has little to do with it. I do focus stacking mostly on AFS or manual focus with a series of single shots. 

Single shots and manual focus will work fine in some scenarios.  But for the moon which is moving across the field due to the earth’s rotation, and clouds are sometimes encroaching, for the stacking to work best, you need as many good single images as possible within the shortest time frame and keeping the relative position of the subject in the same position in the frame.  Of course, all this is based on hand-held not tripod.  Avoiding multiple shutter presses for each set of images is also desirable.  

[drjonb]

4 minutes ago, jaapv said:

Whatever. The proof is the image 😀😀

True, many thanks, much appreciated.

[bags27]

I apologize in advance for my stupidity/lack of experience in this technology, but I'm interested. The lens must be focused at infinity, right? If so, I don't understand how autofocus matters on successive stacking shots. If anything, my instinct says to turn it off so that there's not the occasional misfocus due to glare from the window, etc. But I'm an old zone focus guy.

BTW, I'm very impressed that you can handhold such extensive gear!

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[jaapv]

I do take occasional moon shots and I tend to use manual focus, to avoid an adjustment error of the infinity stop. I also tend to use a tripod as the moon is so bright that we can use shutter times that are short enough that we don’t have to take the movement of the moon into account. 

[drjonb]

2 hours ago, bags27 said:

I apologize in advance for my stupidity/lack of experience in this technology, but I'm interested. The lens must be focused at infinity, right? If so, I don't understand how autofocus matters on successive stacking shots. If anything, my instinct says to turn it off so that there's not the occasional misfocus due to glare from the window, etc. But I'm an old zone focus guy.

BTW, I'm very impressed that you can handhold such extensive gear!

Thanks for your kind words.  In principle, you are right, and the lens should be focused at infinity.  In practice, the moon is one of the few space objects where there is enough contrast to use auto focus, which I prefer to use for the moon.  Also, with the moon, it would be normal to use a telephoto as a wide field image is not required.  It is more of a challenge to get really good focus on stars or planets, and although the magnification feature in the SL2-S does help, a lot of test shots may be required to nail the focus especially when using a lens with a long focal length.  If you are manually focusing with a long lens (or telescope), once you have good focus, it is advisable to lock the lens focus or use tape to ensure the focus cannot move.  For wide field shots of space, for example using a 14mm lens, more depth of field is available, which helps with the focusing and getting some depth of field.

The other challenge with astro photography is that atmospheric conditions change constantly.  This is the major obstacle to getting the focus right.  You have to be a bit lucky and there is even an expression, “lucky imaging” covering this aspect.  Video can also be used to photograph the moon or other objects, and there are several astro apps which will then disassemble the video into separate image files, select the best ones (where atmospheric conditions were least problematical) and then stake the best frames.

Regarding your question on autofocus and stacking; in relation to the moon, due to the earth’s rotation, successive shots with too much time between them, can mean that the moon’s disc has moved too far in the 35mm frame so that alignment is not possible.  I covered this point in one of my posts above.  To achieve a good result with the moon, and to obviate the need to mount camera and lens on a star tracker to eliminate the effect of the earth’s rotation, it is necessary to capture several frames quickly in a matter of one or two seconds.  With the moon, autofocus enables this to be done.  Manually focusing each time will introduce too much delay between frames in my experience.  A lot of my comments here only relate to the moon.  For wide field Milky Way shots, and galaxies, for example, there is little choice but to use long exposures and a star tracker, and a very wide angle lens.

 

I hope this helps, please ask if you have any other questions.  I am no expert but will try and answer them!