Fixing the contrast of a mirror lens

[Fine_Art]

I was out yesterday doing some wildlife photography with the big mirror. 1200 FL, F 4.7

You really need a good software to fix the extreme contrast correction while not building up nasty artifacts. I may try DxO for this. Attached are 3 screenshots showing the difficulty of the contrast sag. This is after correction in RT. It still looks a bit off. Any suggestions on how to make the fur look sharper? There is detail in there, it is hard to see with the dulled contrast.

[ErikKaffehr]

Hi,

These workflow suggested by Bart? http://www.luminous-landscape.com/forum/index.php?topic=87650.msg716838#msg716838

I would try to play around with one of the images if you posted a raw.

Best regards
Erik

I was out yesterday doing some wildlife photography with the big mirror. 1200 FL, F 4.7

You really need a good software to fix the extreme contrast correction while not building up nasty artifacts. I may try DxO for this. Attached are 3 screenshots showing the difficulty of the contrast sag. This is after correction in RT. It still looks a bit off. Any suggestions on how to make the fur look sharper? There is detail in there, it is hard to see with the dulled contrast.

[Redcrown]

Skip to the bottom of the page Eric showed where Bart shows Topaz Clarity.

I higly recommend Topaz Clarity and Topaz Detail for images like yours. The tools are excellent for bringing out contrast and detail in dull, flat images.

[Schewe]

It still looks a bit off. Any suggestions on how to make the fur look sharper? There is detail in there, it is hard to see with the dulled contrast.

Pity you didn't show the basic tonal controls, but based on the histogram, your overall image needs contrast. You prolly want to clip the extreme blacks a bit and increase the midtones.

Also, none of the images actually look "sharp". I notice one of the images was shot at 1/200th of a sec...was this on a tripod with mirror lockup? With a 1200mm lens any little thing impacting sharpness is gonna be magnified...if you can't shoot with mirror lockup, I suggest shooting at no less the 1/focal length of the lens (even on a tripod) if not 2/focal length. A faster shutter speed will help–even if you have to push the ISO. Noise reduction is actually easier than trying to re-sharpening a soft image.

And yes, "Clarity" (or otherwise called midtone contrast) will help...but the bottom line is even with clarity, the post processing sharpening is not really gonna be able to return the sharpness that a slower shutter speed has caused. Perhaps some deconvolution sharpening might help.

Also note that extreme telephoto lenses are gonna lack "contrast" because of the amount of arial haze the image is going through...that's where proper contrast in the post processing can help...which brings us back to tone adjustments...

[Iluvmycam]

Lots of PP. But the bottom line is they are crap and not worthy of use unless it is a last resort.

I've tried them all m43, FF, crop.   One of the five I tried was better than the rest, almost just doable, but it was still subpar. Now, for many of you they are fine, but for me I gave them up. Why fight things unless you need max small size in a lens.

[Fine_Art]

It so happens I bought clarity recently when they had a sale. I had kept my eyes on the stuff for sales based on Bart's recommendation. I just tried it, it makes a big difference.

Not quite a tripod, its a dobsonian mount.  I have 2 fingers on the front edge to point it, 2 fingers and thumb on the focuser wheel and the other hand on the shutter trigger, also helping to point. That is good advise, there was no reason for me to keep to low ISOs with the D600. Old habit I guess. I cant use MLU with wildlife, they barely fit in the frame at 100 yds. Have to track. The DoF is also razor thin so keeping that focus wheel on the right distance is critical.

[Fine_Art]

Rats, when I went to save the enter serial# popped up. I had a look, it was topaz detail that i bought. I will have to get clarity.

[Bart_van_der_Wolf]

Rats, when I went to save the enter serial# popped up. I had a look, it was topaz detail that i bought. I will have to get clarity.

Hi Arthur,

My approach would be to first use 'Clarity' to adjust the tonality, if you cannot fix it any better with RawTherapee first. Then use 'Detail' to bring out the 'small detail' of the fur. Should do the job.

As for the purchase of Clarity, you can ask (if you didn't do that earlier already) for a temporary serial key to test the software, therewith unlocking the possibility to save. The folks at Topaz Labs run weekly Webinars, and usually give out discount coupon codes to the participants, ranging from 20% discount for all plugins up to 50% discount for the product that has the main focus those weeks (currently they focus on their masking plugin). I don't know if Clarity is next on their list soon.

Cheers,
Bart

[Fine_Art]

Hi,

These workflow suggested by Bart? http://www.luminous-landscape.com/forum/index.php?topic=87650.msg716838#msg716838

I would try to play around with one of the images if you posted a raw.

Best regards
Erik

I uploaded to megafile upload. I have not used their hosting before. Members can feel free to play with it. If you get a good result post it for discussion.
http://www.megafileupload.com/en/file/527972/-DSC5710-NEF.html

Note I customized this telescope with a small secondary 15-18%, can't remember the size. I am also not sure on the collimation ,as the temp was falling fast at the end of the day.

I posted this file for the odd neck. I was going to delete it anyway.

[Fine_Art]

This would be ok detail for a print.

[Schewe]

This would be ok detail for a print.

Yes, but...without having the actual image on my calibrated display, I'll still point out that you may still need to scruntch blacks a bit.

[Fine_Art]

Yes, but...without having the actual image on my calibrated display, I'll still point out that you may still need to scruntch blacks a bit.

You are welcome to the nef to show what you mean. You are one of the guys that can probably take a low contrast raw as far as it will go.

I will of course try to experiment to improve it further that what I have so far.

[Bart_van_der_Wolf]

Members can feel free to play with it. If you get a good result post it for discussion.

Hi Arthur,

While the optical quality poses a lot of challenges, it is still possible to wrestle something usable out of it. I used Denoise, FocusMagic, Clarity, and Detail to get the attached result (cropped and downsampled, and a full-size crop). The original size looks reasonably printable.

Cheers,
Bart

[Fine_Art]

For a $600 lens I cant complain. I am not out to take Nat Geo big game shots with it. I enjoy being out in the park taking shots of the wildlife at enough distance for them to feel in control. Over 1/2 hr of shooting this herd they moved closer grazing, then moved in an arc around me. They were in control of the distance. Some were watchful, which makes a nice shot, some were sitting in the crass looking half asleep grazing a circle around themselves. In the Tetons you can get much closer. This is a herd on the border of the Rockys and Alberta at Waterton Lakes. They are far more alert to hunters.

I find it hard to get the color right when the contrast is stretched. It is too bland or way gaudy like I posted above.

[Fine_Art]

The view of the herd with an 85mm

[Fine_Art]

DxO makes easy work of the file. I'm impressed. 2 quirks:
it got the temp wrong.
Set active lighting to medium.

If you use a mirror lens DxO seems to be the way to go!
 From this tif I would do custom sharpening.

[Fine_Art]

I am still amazed by how well DxO handles this unusual situation. I don't know or use the program. I downloaded a 30 day trial to test this at about 2:45 PM, going down the interface learning the sliders I had a decent image at about 3pm. This was a total surprise to me, I had spent hours playing with various sliders in RT, a program I feel I can use well, to less effect in this situation.

I filled 2 32gig cards with shots of this herd. All are basically animal portraits from the angle of view with the lens. I can now make short work of them copying those settings as a starting point.

The mirror should give me a sag in contrast at around 50-60 lp/mm according to the MTF of these types of lenses. I was hunting for a way to boost that frequency. DxO seems to have it covered in their active lighting, whatever that means.

[Grizz]

Figured I'd have a turn at it. LR adjustments and Topaz Clarity.

[Fine_Art]

Not bad. The challenges are the fur going redish, the animal in shadow going blue, the thick hair on the neck going too black. I found these hard to control in RT as well. Someone with capture one linear may have an advantage if they can fit their own curve. The theory of why it is difficult is interesting. Due to the very low contrast it seems like a great opportunity for extreme ETTR. I think I adjusted, after viewing the first shot, to + 1.67ev. All the data should be packed into light levels with very fine gradations. And yet it is hard to work in most software.  I have no idea why.

[Grizz]

I tried to reduce the reddish and the bluish, But not sure its any better.