Critique my image

Just bought that first macro lens? Post here to get helpful feedback and answers to any questions you might have.

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Smokedaddy
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50D Hot pixels

Post by Smokedaddy »

My 50D has a TON (like a lot) of hot pixels really making it totally time consuming to clean them up in Photoshop, but doable. I always shoot RAW in my landscape photography but since doing macro-stuff I've only shot in JPG's since the stack program won't accept them. After reading the forums here I shot a test stack in RAW and converted them to TIFF in Photoshop CC. Naturally the files are HUGE so I'll have to buy one of those 128GB Compact Flash cards someday. The good news being the hot pixels are history by doing this. I was totally blown away at the success!

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rjlittlefield
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Post by rjlittlefield »

Referencing your second post above here, at http://www.photomacrography.net/forum/v ... 922#199922 .

Silly question, but is what you've posted really the DMap? It looks more like PMax.

I'm not seeing loss-of-detail halos like I would expect with DMap around the front antenna which is far in front of the "forehead", and I am seeing vague fuzzy halos in the background, which I would not expect from DMap but are typical of PMax.

--Rik

Smokedaddy
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Post by Smokedaddy »

It is a DMap image promise. I'm taking about the dark perimeter areas around the subject. I some what fixed about 90% of it in PS and I don't have the original that was messed up.

Guess I was asking if I needed the "project" and the generated DMap and PMax images to use the retouching feature in the program.

-JW:

Smokedaddy
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Post by Smokedaddy »

Maybe I just over processed it in PS and created all the problems myself, dunno. Here's another.

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rjlittlefield
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Post by rjlittlefield »

Smokedaddy wrote:Guess I was asking if I needed the "project" and the generated DMap and PMax images to use the retouching feature in the program.
"Yes" is a pretty good answer.

You absolutely need the project to retouch from source, because that's where any alignment information comes from.

Sometimes people save just the DMap and PMax output files and then ask if there's some way to use Zerene Stacker to retouch between just those two. That is possible, but only by a complicated and circuitous route. It involves creating a new project that contains the DMap and PMax as source files, turning off alignment, and generating a new stacked output that ends up serving as just a placeholder. I think this is not the sort of thing you should be doing as a relatively new user. It's better to build workflow habits that use the software as intended, for example saving the project if you think there's the slightest chance that you might want to do retouching later.
Here's another.
In this image, the first thing that clubs me over the head are all those dust trails in the background. You would be doing yourself a great favor to clean your sensor.

I also see some "warm pixel" trails. Those are the brighter ones, mostly red. Various attacks on warm pixel trails are: 1) fix them with Photoshop's "healing brush", 2) retouch from a single source frame in Zerene Stacker, or sometimes 3) try shooting raw because some raw converters will eliminate hot pixels during raw conversion.

After more study, I see some blobby halos in the background, most obvious inside the bend in the legs. There are also some around the palps, the eyes, the antennae, and the upper thorax.

The best attack on those halos is to move the DMap contrast threshold slider to a higher percentile. The best setting for this purpose is to move the slider so high that the entire background goes "black in preview", except for a very narrow band (a few pixels wide) around the edge of the subject.

Sometimes it works well to run DMap a couple of times with different thresholds. Typically one threshold would be relatively low, leaving some halos in background but a clean rendering all over the real subject, while a second threshold would be much higher, eliminating all halos in background but perhaps losing some detail in low contrast areas of the subject. Given both DMap outputs, it's then relatively easy to retouch from the high-threshold output into the low-threshold output, so as to clean up the background. This process is illustrated in the Advanced Retouching tutorial.

I hope this helps!

--Rik

Smokedaddy
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Post by Smokedaddy »

Thanks Rik,

I didn't realize those trails were dust mites. :oops: I thought the 50D was self cleaning on startup. I'll search the Internet for a manual and do some reading (seems like that's all I've done lately is read). <g> I have a Arctic Butterfly so I'll use that if it's acceptable.

I"ll simply re-stack these puppies and save the project this time, that's no a big deal.

BTW, shooting RAW eliminated the hot spot problem 100%, including those streaks (that's why I thought they were something else), as shown in my antennae posting.

Thanks for the tip on the CT slider too. I did read the tutor but still didn't quite understand its function. I had the slider at 3 or 4. :roll:

-JW:

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Smokedaddy
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Post by Smokedaddy »

rjlittlefield wrote: The best attack on those halos is to move the DMap contrast threshold slider to a higher percentile. The best setting for this purpose is to move the slider so high that the entire background goes "black in preview", except for a very narrow band (a few pixels wide) around the edge of the subject.
That worked perfect, so I"m going forward instead of backwards now, plus I've eliminated all the pixel problems.

BTW, I didn't shoot this batch over in RAW but ran it again with the original .JPG's to experiment, so all the hot pixels are still there. I need to purchase a 128GB compact flash card before shooting another sizable stack of images. Anyway this time I tried slabbing and used SlabberJockey to generate the .XML file, then stacked those. I looked at your retouching video again as well as Michael Erlewine(s) and tried retouching. I have a better understanding how to use it now but still need a lot more practice.

Basically is the concept of retouching to scroll through the images in the left windows in Zerene to find lets say an antenna section (or a portion thereof) in the stack that is in focus, then in the right windows use the brush circle to remove the blurred areas (halos) if they exist.

Thanks again for the help,
-JW:

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