Symptoms of Movement?

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Deanimator
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Symptoms of Movement?

Post by Deanimator »

I just shot this stack of 114 shot with:

Canon T4i, manual 1/250, ISO 100
Minolta 50mm manual reversed onto two sets of extension tubes
two Amazonbasics manual flashes set to 1/32 power
Wemacro set to 88um
stacked with Zerene

What are those black streaks surrounding the subject? Are those artifacts caused by movement?

Something common to Pmax in Zerene?

Given my somewhat rudimentary equipment, I'm relatively happy with the results. However, this isn't the first time I've seen these streaks.

What can I do to eliminate them?

Edit: It'd be helpful to attach the picture...
Image

Pau
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Post by Pau »

They are dust trails: the sensor has very small dust particles (you must be able to see them at each individual frame) and because the field of view -and magnification- changes during focus stacking to maintain the subject proportions the software adjusts the frame size and so the position of the dust spots.

How to avoid them?
- clean the sensor (although it's very difficult to have it perfectly clean)
- use a telecentric lens that doesn't change magnification with the distance.

(there is some small movement, if not the lines would look straight, but nothing to worry about)
Pau

Deanimator
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Post by Deanimator »

Pau wrote:They are dust trails: the sensor has very small dust particles (you must be able to see them at each individual frame) and because the field of view -and magnification- changes during focus stacking to maintain the subject proportions the software adjusts the frame size and so the position of the dust spots.

How to avoid them?
- clean the sensor (although it's very difficult to have it perfectly clean)
- use a telecentric lens that doesn't change magnification with the distance.

(there is some small movement, if not the lines would look straight, but nothing to worry about)
Could it be the lens itself?

I don't recall getting those streaks with my Tokina 100mm macro.

That's a very old lens, probably older than some of the people who post here.

I also saw reference on the Zerene website to streaks being caused by changing of the framing of shots, sometimes due to shooting angled downward, which in fact the rail and camera are.

rjlittlefield
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Post by rjlittlefield »

These look far too sharp to be anything on the lens. Usually dirt on the lens will manifest as huge fuzzy blobs, unless you're using something like a fisheye lens with enormous DOF.

If there is a difference from one lens to another, it is probably in the way that image size changes as you step focus. That change is much less with some lenses than others, and less change makes the trails shorter.

The other kind of streaks that you've mentioned are "edge streaks". They look completely different. See slides 83 versus 84 at http://zerenesystems.com/presentations/ ... 151009.pdf . (This is the "Recommended Presentation Slide Set" mentioned at https://zerenesystems.com/cms/stacker/d ... rialsindex .)

--Rik

Deanimator
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Post by Deanimator »

rjlittlefield wrote:These look far too sharp to be anything on the lens. Usually dirt on the lens will manifest as huge fuzzy blobs, unless you're using something like a fisheye lens with enormous DOF.

If there is a difference from one lens to another, it is probably in the way that image size changes as you step focus. That change is much less with some lenses than others, and less change makes the trails shorter.

The other kind of streaks that you've mentioned are "edge streaks". They look completely different. See slides 83 versus 84 at http://zerenesystems.com/presentations/ ... 151009.pdf . (This is the "Recommended Presentation Slide Set" mentioned at https://zerenesystems.com/cms/stacker/d ... rialsindex .)

--Rik
I'm going to do a manual cleaning after I buy a brushless blower (the only one I have is 30+ years old and has a brush on it.

After that, I may have to take in to be cleaned. Not sure where to do that in NE Ohio...

Chris S.
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Post by Chris S. »

Deanimator wrote:After that, I may have to take in to be cleaned. Not sure where to do that in NE Ohio...
If my experience is any guide, skip the "professional" cleanings--the camera shops whose work I've seen aren't picky enough for a macro photographer. The small apertures we use show dust particles too tiny for most professional shops to bother with.

For me, cleaning a sensor requires a low-powered stereomicroscope and oblique light (sensor loupes do not show all the small dust). I start and finish with a blower, first to remove lightly-adhering particles, and later to remove cleaning fibers. In between, use of some "wet" cleaning method is nearly always necessary, to remove sticky particles such as skin flakes.

--Chris S.

Deanimator
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Post by Deanimator »

Chris S. wrote:
Deanimator wrote:After that, I may have to take in to be cleaned. Not sure where to do that in NE Ohio...
If my experience is any guide, skip the "professional" cleanings--the camera shops whose work I've seen aren't picky enough for a macro photographer. The small apertures we use show dust particles too tiny for most professional shops to bother with.

For me, cleaning a sensor requires a low-powered stereomicroscope and oblique light (sensor loupes do not show all the small dust). I start and finish with a blower, first to remove lightly-adhering particles, and later to remove cleaning fibers. In between, use of some "wet" cleaning method is nearly always necessary, to remove sticky particles such as skin flakes.

--Chris S.
After learning [yet again] that you can't get serious photo gear and accessories in NE Ohio, I ordered a blower and wet cleaning tools early this morning after I got home from work. I got the stuff recommended by quirky YouTube personality Theoria Apophasis.

Unfortunately, none of the stuff is getting here before the 11th, so I'll just have to soldier on as-is, unless I somehow stumble across at least a blower at Dodd or Pixel Connection.

Deanimator
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Post by Deanimator »

Pixel Connection in Avon had cleaning gear not on their website, so I'm going to try to clean the sensor when I get home tonight or tomorrow morning.

Chris S.
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Post by Chris S. »

How did your cleaning go, Deanimator? If it's anything like my first time cleaning a DSLR sensor, the answer will be "frustrating." There will be some tough spots that stubbornly resist a wide swab, which upon removing can cause a wider mess. And sometimes, grease seems to appear from nowhere during the cleaning. (New cameras sometimes have greasy gunk around the sensor, and the first cleaning can smear this onto the sensor; if this happens to you, just keep cleaning with additional swabs--once you get all this peripheral grease off, it should be gone forever.) Rest assured, it gets easier.
Deanimator wrote:I got the stuff recommended by quirky YouTube personality Theoria Apophasis.
"Quirky" is a very polite word for this personality!

I like his recommendation for sensor swabs well enough. Also agree with him that you'll want PEC pads or similar for additional cleaning. I lash slices of PEC pads over pencil erasers for spot cleaning. (And also use PEC pads on lenses.)

I disagree with him (and just about everyone else) on insisting on Eclipse cleaning fluid, which is just alcohol plus marketing. In my experience, any common alcohol works as well--including vodka, rubbing alcohol, and hardware-store methanol.

--Chris S.

Deanimator
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Post by Deanimator »

Chris S. wrote:How did your cleaning go, Deanimator?
I've only been home from work for less than 1/2 hour. I think that I'll pass on trying to clean a camera sensor at 2:15 in the morning! I'll give it a shot after I get some sleep.

Pau
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Post by Pau »

Chris S. wrote:--including vodka
Where do you put the vodka? :lol:
Pau

Chris S.
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Post by Chris S. »

Pau wrote:
Chris S. wrote:--including vodka
Where do you put the vodka? :lol:
Well, it IS a multi-tasker. . . . ;)

Deanimator
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Post by Deanimator »

Pau wrote:
Chris S. wrote:--including vodka
Where do you put the vodka? :lol:
And I'd highly recommend UNflavored vodka...

Deanimator
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Post by Deanimator »

I did a dust detection image... and found nothing. Not sure why.

I then did a couple of cleaning cycles with the camera mechanism.

I then blew the sensor area out with a hand blower.

I'm doing a stack now to see what happens.

The subject is [almost] exactly as it was for the posted picture, so changes should be readily apparent.

Deanimator
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Post by Deanimator »

Streaks are still there, so on to wet cleaning.

Interestingly they don't initially appear in Zerene, only appearing part way through the stack.

It'll have to wait until tomorrow morning after I get home from work.

Interesting that I didn't see anything when doing the recommended test image for dust...Image

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