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Thread for 90-280 images?


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Early morning prey in the mountains. Golden Eagle on red fox. Photo taken from shelter.   90-280mm @ 280mm on the CL. ISO3200, f4, 1/160 sec. Hello guest! Please register or sign in to view the hidden content. Hallo Gast! Du willst die Bilder sehen? Einfach registrieren oder anmelden!

Magical Mornings  Leica SL, Leica APO 90-280 Hello guest! Please register or sign in to view the hidden content. Hallo Gast! Du willst die Bilder sehen? Einfach registrieren oder anmelden!

Eurasian bullfinch.   SL + 90-280mm at 280mm. Prefocussed lens, hoping for the bird to be frozen in the focus plane with an interesting wing gesture... In this case the focus plane starts from the birds eye, extending 4-5 cm backward. The 90-280 has loads of micro-sharpness. The oof rendering can be somewhat harsh/disturbing, but this can be mediated in post. But a beautiful lens, all in all. Hello guest! Please register or sign in to view the hidden content. Hallo Gast! Du willst die Bild

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Impossible to follow TheGod Particle's shot, thats brilliant.  Now jhulton's too - I will get my coat.

Planying with separation with the lens in Suburbs....

Edited by Sjz
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3 hours ago, Sjz said:

Impossible to follow TheGod Particle's shot, thats brilliant.  Now jhulton's too - I will get my coat.

Planying with separation with the lens in Suburbs....

Thank you for the kind words 

Your shot makes me feel like I’m sitting in the garden on a lazy sunday afternoon 

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  • 2 months later...

The jets flew past my bedroom window earlier this morning. The 90-280mm may lack the range but the 47MP of SL2 makes up for more allowable cropping.

15 continuous shots taken on AFC Zone focusing / continuous medium drive / wildlife profile all shots with accurate focus.

untitled-1000695-3 by sillbeers15 Edited by sillbeers15
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I posted this earlier in the SL2 thread, but it is as much an accomplishment of the lens as the camera, so I’m adding it here.

This is a photograph from four nights ago of the Rho Ophiuchi Cloud Complex. It is located in a rich portion of the Milky Way on the border between Scorpius and Ophiuchus. It contains star forming regions (molecular clouds), a globular cluster, and lots of interstellar dust.  The color contrasts make it a really fun subject for photographers.

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These were taken at extreme distance late yesterday evening in north east England at 20:20 BST for the Heron and 21:14 for the Barn Owl. Floating ISO - 3200 for the Heron and 6400 for the Owl.  1/1000s for the Heron, 1/800s for the Barn Owl.  AFc and Field AF.  90-280 at 280 on Leica SL1.   Continuous medium drive rate for the shutter release. Both are cropped to  900px from full-frame. With a little bit of adjustment in LR, given the poor light and high ISO  detail is surprisingly acceptable.

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On 7/27/2020 at 3:25 PM, Franka373 said:

Please discuss the details of your rig and software.  Amazing and encouraging!   

Sure.  For this shot I used the 90-280 on an SL2 with a focal length of 280 and the aperture wide open at f/4.  The image is cropped to 4:3 To get rid of a little negative space but is otherwise the entire frame.  The camera and lens were mounted on my telescope travel mount, a Rainbow Astro RST-135, with a Gitzo Systematic series tripod.  The telescope mount is overkill for this focal length—probably could have gotten away with a lighter weight tracker—but it does a good job unguided up to about 90s at 300mm or less. 

This is a stack of 48 separate 1 minute exposures.  I think I had to throw out two of the 50 or so I took because stars were not as small and round as I wanted.  No dark, flat, or bias frames were used but LENR was turned on in the camera. ISO was set to 1600.  Focus was adjusted manually every twenty to thirty minutes as the lens cooled to ambient and as temperatures fell after dark.

I used PixInsight to align and stack the images.  Photoshop would have worked nearly (but not quite) as well.  The advantage to using PixInsight or some other dedicated astronomy software for stacking the images is that it has more sophisticated algorithms than just Median Combine or Average.  Median leaves more noise than average, but average doesn’t do a good job with satellite trails, hot pixels, cosmic ray strikes, or beta particles from radioactive decay of iodine in the cover glass over the CMOS chip. In other words, transient, spurious noise.  A sigma clip combine method of some sort gives you the best of both average and median combine.

The one significant challenge in this image was that the readout in the SL2 seems to run separately for the four quadrants of the chip.  Presumably this is to allow a high speed readout in parallel.  Somewhere along the way In the electronic amplification, the four quadrants are not identical in brightness or color.  Very close, but not the same.  One quarter of the image was a bit redder, one quarter a bit bluer, and all four were slightly mismatched in brightness.  It is possible that flat frames would have addressed this, but it is so buried in the shadows that I doubt it. You only see it with lots of exposure compensation (“stretching” to an astrophotographer). Since this is a stack of images slightly mid-aligned due to imperfections in tracking over a couple hours the quadrant edges were slightly blurred as well making correction a pain in the neck.  I compensated manually in Photoshop.  Need to play around with other gain levels to minimize this issue in the future.

Color balance and stretching were performed in PixInsight after the images were combined. Also very light noise reduction. I left a fair amount of noise in the image since Too much reduction tends to create splotchy or plastic backgrounds.  The quadrant issue was addressed in Photoshop.  Everything else was just Lightroom adjustments to contrast, brightness, white point, and dehaze. The dehaze effect does a nice job of improving contrast on images with dust lanes like this one. I also used the Texture effect in the negative direction to both minimize the visibility of the noise and to make faint stars less prominent.It doesn’t technically shrink them or sharpen them, but it dims their edges.  Think of it as a reduction of micro contrast and an increase in large scale contrast. Overall, fairly simple processing just done to taste.

A better result might have been achieved with LENR turned off but with a stack of dark frames incorporated into the processing.  I haven’t tried that yet with the SL2.  If you just skip the LENR entirely and skip dark frames as well the banding is really, really bad at ISO1600 with 1 minute exposures, so you need either LENR or (possibly) darks.  Darks need to be temperature matched, though, which could be a problem where I was shooting—it was 75F at sunset and 48F by midnight.

That’s probably more info than you were looking for, but there may be some interested in trying out this camera and lens for deep sky widefield work.  The lens is slower than what would be optimal, but otherwise very good indeed.  Oh, I also made a couple cosmetic corrections on very bright stars.  Vignetting had caused some “negative” diffraction spikes—pie shaped wedges that were cut out of two sides of Antares in particular.  I cut and pasted and rotated to fix those.  It’s a common problem with camera lenses as opposed to telescopes. Mirror boxes, light baffles, and other things intended to minimize ghosting and flare can be a touch too aggressive off axis for bright stars.

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  • 4 months later...

A quick Sunday Morning Stroll, 1h on foot around home. I decided to take the 90-280 out again, it had been sleeping in the Photo Bag for too long :) 

SL + 90-280

 

 

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On 5/13/2020 at 8:42 PM, Sjz said:

Impossible to follow TheGod Particle's shot, thats brilliant.  Now jhulton's too - I will get my coat.

Planying with separation with the lens in Suburbs....

Very nice image!

Thanks!

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On 7/27/2020 at 12:06 PM, Jared said:

I posted this earlier in the SL2 thread, but it is as much an accomplishment of the lens as the camera, so I’m adding it here.

This is a photograph from four nights ago of the Rho Ophiuchi Cloud Complex. It is located in a rich portion of the Milky Way on the border between Scorpius and Ophiuchus. It contains star forming regions (molecular clouds), a globular cluster, and lots of interstellar dust.  The color contrasts make it a really fun subject for photographers.

Nice shot! Do you recall the exposure information by chance? EXIF data? 

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