Why is photo sharpening necessary

[sreynolds]

Almost all my images benefit from sharpening - I'm using GIMP photo editor. The two images below are a rather extreme example, but the blurry image is much improved by sharpening, without any apparent (to me) degradation. Subject in Hydropsychidae larva. The details derived by the sharpening process must be present in the original image. Is there some adjustment to be made in the camera configuration that would accomplish the sharpening up-front? Is there a reason this is not desirable? Would more or fewer pixels help? Maybe higher ISO speed? I have 2 mirrorless cameras - Olympus Pen-E PL7 and Canon M200, and they both behave similarly in this regard. Thanks.

PA040009_1.JPG (111.39 KiB) Viewed 4324 times

original

PA040009a_1.JPG (189.33 KiB) Viewed 4324 times

sharpened

[Scarodactyl]

In extreme macro and micro we are always near to the diffraction limit relatively speaking, not much we can do about that (nothing at all past a point). But we know diffraction blurs things, so by subtracting a blurred version of your image from the image you can partially reverse it. It seems dumb but it works (blind deconvolution).

[J_WISC]

blind deconvolution

Thank you for providing the term for this.

Now I’m wondering whether better stacking software has settings for this.

https://en.wikipedia.org/wiki/Blind_deconvolution

[Topcode]

blind deconvolution

Thank you for providing the term for this.

Now I’m wondering whether better stacking software has settings for this.

https://en.wikipedia.org/wiki/Blind_deconvolution

May i recommend the use of registax? Its intended mainly for planetary astrophotography, but ive used it for correcting CA, color correction, and some sharpening, on my microphotography.

[bkt]

Hi,

I've a photo port to c-mount adapter, which came with a 5mm extension ring. I used it that way for some days, but my pictures were all disapointing.

I was then told to remove this extension ring, which is supposed to be used with specific cameras, maybe with cs-mount cameras (CCD not at the same position)... My pictures are since much sharper (camera or CCD being much closer to focus plan).

I now suspect my camera/CCD still isn't perfectly in the focus plane. I found a variable length tube, but I'll have to rework it.

That is a blurry image I got without the expansion ring. A stack of images. I believe I could get better than this by fine tuning the photo port tube length:



The same picture, processed by an online IA:

[sreynolds]

I believe I could get better than this by fine tuning the photo port tube length

I can well understand how the wrong C-mount adapter would result in poor images - every camera lens-system has a flange focal length which is the distance from the mounting flange of the lens on the camera to the plane of the sensor. 'C' and 'CS' mounts are different by about 5mm (actually 5.026mm). I am using direct projection of the intermediate image formed above the photo tube placed directly on the camera sensor without any intervening lenses; getting the camera parfocal with the eyepieces involved finding the right spacers - in the case where intervening projection/reduction lenses are involved, if you stick to what the manufacturer offers for adapters, things should line up properly and not necessitate any kind of adjustable tube. I don't know what scope or adapters you are using, so I can't say anything more. (your pictures look good to me as they are)
I was satisfied with Scarodactyl's explanation -

In extreme macro and micro we are always near to the diffraction limit relatively speaking

- my subjects are mostly alive and less-than-optimally prepared which augments the focus problem for me.

[bkt]

my subjects are mostly alive and less-than-optimally prepared which augments the focus problem for me.

But seeing your first image, with nothing or not much in focus, I think you could have an issue with your setup. Aren't the images better in your eyepiece?

This is a video I took, of a live big worm at 4x, it is a bit blurry only, not that much:

I don't know what scope or adapters you are using

An infinity scope, without any optics in the adapter, so I should have the intermediate image at precise location in the tube. I think I still could be off by some millimeters with a stock 1x adapter.

I ordered that variable length tube, but it is too long, I'll have to shorten it by 10 to 15mm for my needs:



That is without any processing, an hydra under a Bresser Erudit DLX, it doesn't look that much blurry to me either:

[bkt]

Almost all my images benefit from sharpening - I'm using GIMP photo editor. The two images below are a rather extreme example, but the blurry image is much improved by sharpening...

Hi, I just found a similar beast on a prepared slide, which made me think again about your sample pictures.

Checking again, seems you could first hit a depth of field issue, parts only seem to be more sharp or in focus, like here:

PartiallyInFocus.JPG (23.41 KiB) Viewed 757 times

Such slides are thick, and those animals are to big to be rendered using a single shot. Following is an image without sharpening, but with a stack of 268 pictures:


Maybe, see this other topic, about quick stacking using short 8 to 16 seconds videos, with some patience, this works also for moving animals: viewtopic.php?p=142491#p142491