Search found 35 matches

by palea
Wed Mar 25, 2020 9:34 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sample density needed to resolve Rayleigh features
Replies: 40
Views: 4818

If we can make similar improvements in understanding sampling and image reconstruction, that would be superb! I don't see why it wouldn't be possible. However, the depth of field example mentioned gives me a question and a corollary which I think are relevant. As context, the only FAQ entry whose t...
by palea
Sat Mar 21, 2020 6:53 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sample density needed to resolve Rayleigh features
Replies: 40
Views: 4818

If you see something that I've messed up or seem to have a wrong understanding about, please let me know so we can get it fixed. Hi Rik, I think I'd like to suggest a different framing. Zerene gives you a thorough knowledge of alignment and focus stacking. Similar depth and nuance exists in most ot...
by palea
Sat Mar 14, 2020 9:23 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sample density needed to resolve Rayleigh features
Replies: 40
Views: 4818

I suggest also reviewing earlier discussion in the thread and links starting at https://www.photomacrography.net/forum/viewtopic.php?t=33724 Any particular aspect of it? About half the thread is pretty solid, I think, but I chose not to bump it when I looked a couple years ago because attempting to...
by palea
Tue Mar 03, 2020 6:31 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Sample density needed to resolve Rayleigh features
Replies: 40
Views: 4818

So the number of pixels you desire based on Rik's example needs to be increased for Bayer sensors, up to a factor of 2 depending on the subject. 2sqrt(2) if the feature of interest's oriented along the diagonal of a grid of square pixels. And, as the sensor's two dimensional, the total number of pi...
by palea
Tue Dec 31, 2019 9:50 am
Forum: Equipment Discussions
Topic: Ca 2020 Continuous Lighting Panels?
Replies: 2
Views: 452

Re: Ca 2020 Continuous Lighting Panels?

it just a matter of of looking at specs and reviews? If you can find a panel with photomacrographic specifications or reviews I'll be impressed. I'd suggest doing the math on the lux and LED spacing relative to your diffuser's transmission and shutter speed, effective aperture, and ISO requirements...
by palea
Fri Dec 27, 2019 9:59 am
Forum: Equipment Discussions
Topic: Panasonic Lumix cameras & Post Focus
Replies: 76
Views: 40973

Hi, I have some follow on questions about how post focus compares to focus bracketing. These are motivated by curiosity over tradeoffs which might favor one method or another in certain circumstances. It's mentioned earlier in this thread that brackets are displayed as they progress. Does this mean ...
by palea
Mon Dec 02, 2019 9:22 am
Forum: Equipment Discussions
Topic: Lomo 3.7x finite vs 120G
Replies: 75
Views: 3750

higher magnification than the simple infinite focal length multiplication due to the longer minimum extension Hi Ray, maybe I missed it in the back and forth, but how much extension are you adding? Presumably there's some back and forth to find an optimum? (As an aside, I arrived at Lou's method an...
by palea
Sun Oct 27, 2019 7:21 am
Forum: Equipment Discussions
Topic: Plustek 120 Medium Format Scanner Lens Test Results
Replies: 18
Views: 1707

It still needs some final editing for spelling errors etc, so let me know if you spot any errors, I'm sure there are a few. Looks good to me, other than the 135mm link at the end pointing to the 2018 test, which is perhaps expected. As usual, my ranking of the lenses is somewhat different than your...
by palea
Sat Oct 26, 2019 12:27 pm
Forum: Equipment Discussions
Topic: Plustek 120 Medium Format Scanner Lens Test Results
Replies: 18
Views: 1707

I need to make sure that I take a look at short focus with future testing! Cool! I'll look forward to the details when your 150mms as tube lenses review is out (not seeing them on your website as yet). My testing has been starting to move this way as well, though I've been thinking more in terms of...
by palea
Sat Oct 26, 2019 8:29 am
Forum: Equipment Discussions
Topic: Plustek 120 Medium Format Scanner Lens Test Results
Replies: 18
Views: 1707

It appears that really well corrected lenses, like a Macro Varon, work wonderful on extension but they really badly on a tube lens. On the other hand lenses that are okay or just average on extension, like a Componon 4/28 or 4/35, put these on a good tube lens and they work beautifully on a tube Hi...
by palea
Sun Jun 09, 2019 8:51 pm
Forum: Equipment Discussions
Topic: Coverage and Stacked Lenses - Constraints?
Replies: 6
Views: 1234

Hi Rik, thanks for the link. It's probably no surprise my anecdotal experience with vignetting is consistent with your figures there. I guess my previous post can be more compactly stated as one way of getting around far to the rear element placement is to fill the front element of the forward facin...
by palea
Sun Jun 09, 2019 4:43 pm
Forum: Equipment Discussions
Topic: S1R pixel shifting
Replies: 35
Views: 2766

Some day it may be possible to superimpose the sensor pixel shifting movements on the vibration reduction movements, but no camera does that now. Hi Lou, a closer look at the feature set of the Olympus E-M1X may be helpful. :wink: It's also feasible to generate superresolution images by aligning fr...
by palea
Sat Jun 08, 2019 8:31 am
Forum: Equipment Discussions
Topic: Coverage and Stacked Lenses - Constraints?
Replies: 6
Views: 1234

I fear there is a gap between thin lens theory and the realties of pupils. I suspect it goes beyond pupils. Regardless of format, the forward facing (rear) lens has to look through the reversed (front) lens/close up lens/microscope objective. As I currently understand it, this means the entrance pu...
by palea
Fri Feb 15, 2019 2:46 pm
Forum: Equipment Discussions
Topic: Switch to Panasonic good idea or not worth it?
Replies: 4
Views: 2879

Re: Switch to Panasonic good idea or not worth it?

GX820 I presume this is a typo for the GX800/850 as, so far as I know, there's not an 820 (or 810). Given the objective of handheld stacking it may be worth considering a body with IBIS, particularly if you're thinking the Olympus 60mm over the Panasonic-Leica 45mm as the Olympus lacks OIS. Some fo...
by palea
Tue Jan 29, 2019 4:36 pm
Forum: Equipment Discussions
Topic: Panasonic Lumix cameras & Post Focus
Replies: 76
Views: 40973

"Method A computes the weight for each pixel based on its contrast and then forms the weighted average of all pixels from all source images. This method works better for short stacks and preserves contrast and color." Good point; I'd forgotten about method A as I didn't use it much when I was worki...