After f/16 I see the dirt on the sensor... but no hint of any of the strange shapes on the glass... You will never see the shapes on the glass, because the lens surfaces will never be in focus enough to see them. This is why you can have scratches, chips, etc on a lens and they will never show up a...

I have been thinking about using a burning laser (like the kind used to engrave stuff) to burn off the fungus from internal elements. I've tried it a little bit but it is tricky since reflective surfaces on the lenses can send the laser into your eyes, burning off your retina instead of the fungus....

I've compared a few lenses with mild fungus to their pristine counterparts, and saw no effect. Never tested anything with as much as the one shown above though. Also have purchased a few lenses that had mild surface fungus, and found it usually cleans off quite easily just with moisture from breathi...

It doesn't take huge misalignment of the front standard to mess things up. 1 degree will produce a 3.5mm shift on 200mm extension. You could try tweaking the bellows a bit to see if you can improve/degrade the decentering. Even on fairly stiff bellows it's possible to move 1 degree without doing dam...

I'm getting anxious about the next Electronics Swap, scheduled for March 10. It's going to be at West Valley College, same as all of last year. It's an excellent location, and hopefully will stay there for a long time to come. 6AM start time, but most folks are not set up until 7AM or so. That won't...

Interesting information about what you describe. It may be confusing that I did a “quick & dirty” test, and used some coins as objects to be photographed. (Maybe subconscious inspired by examples here on the forum? 8) ) Indeed, by that it comes down, “how” the coins are illuminated by the light shi...

I've played around with stitching coin images using a few methods. The differences mainly come down to lighting. Lighting on full coins is critical for things like luster and color, but on detail shots the most important thing is contrast on local surface features to best show the details. I started...

Here's another beautiful 105PNA from Japanese eBay seller. Great price for the condition IMO.

Serial number is 1310

https://www.ebay.com/itm/395198303329

That would fit a 28mm inner diameter photoport on older microscopes. I think Leica S or M microscopes had those? So yeah, most likely relay lenses for microscope photography. EDIT: https://www.naturamediterraneo.com/Public/data9/Guido%20Gherlenda/phototubes.pdf_201422202543_phototubes.pdf "American...

I can imagine projection eyepieces looking like these. The front cylinder would fit standard eyepiece tube, and the optics would intercept the light before it focuses at the standard place, and redirect it to focus farther back and bigger. But this is speculation. I have never seen anything that lo...

They look like tube lenses of some sort but they are not converging. Mount diameter is 52.5mm.

mkbn wrote: ↑

Tue Feb 13, 2024 11:36 am

Which would be neat! I really love mine and I got it used at an OK price,

It was just released and you were already able to buy it used? That seems odd. Why did the seller let it go?

The presumption that f5.6 is best at 1:1 may not be correct. Macro lenses are generally optimized for their highest magnification, so it may be that you get better performance at wider aperture than you would when doing portraits. There is also the question of what "best performance" means. Some loo...

Definitely precarious.

This thread went pretty far sideways. @Igor, have your original questions been answered?