Search found 1302 matches

by enricosavazzi
Tue Nov 24, 2020 2:36 pm
Forum: Equipment Discussions
Topic: Mitutoyo gamme NIR pour macrophotographie
Replies: 3
Views: 61

Re: Mitutoyo gamme NIR pour macrophotographie

The M Plan Apo NIR series is corrected from 480 to 1800 nm, so they likely display chromatic aberration in the 400-480 nm range (blue and indigo). Anything above 1,000 nm likely cannot be recorded with a Bayer sensor even after removing the NIR- and NUV-cut filters of the camera, so you would be pay...
by enricosavazzi
Mon Nov 02, 2020 1:03 pm
Forum: Equipment Discussions
Topic: Review of Mitakon Creator 85mm f/2.8 1-5X Mark II
Replies: 9
Views: 904

Re: Review of Mitakon Creator 85mm f/2.8 1-5X Mark II

I found this lens's narrative arc very strange. One kind of gets the impression this company has no idea what they're doing, but I almost never follow normal camera lens development so I don't know if this kind of thing is normal? I would not say it is normal, but it is not unheard of either, espec...
by enricosavazzi
Mon Nov 02, 2020 12:45 pm
Forum: Equipment Discussions
Topic: Review of Mitakon Creator 85mm f/2.8 1-5X Mark II
Replies: 9
Views: 904

Re: Review of Mitakon Creator 85mm f/2.8 1-5X Mark II

The redesign caused the nominal aperture to increase from f/2.8 to roughly f/4.8-f/5.6 I would suggest the aperture decreased or was reduced. The way I use the term aperture value in the review is in the sense of f/ratio. This is the aperture as expressed in several of the geometric optics formulas...
by enricosavazzi
Fri Oct 30, 2020 2:26 pm
Forum: Equipment Discussions
Topic: Review of Mitakon Creator 85mm f/2.8 1-5X Mark II
Replies: 9
Views: 904

Review of Mitakon Creator 85mm f/2.8 1-5X Mark II

I have written an in-depth review of the Mitakon Creator 85mm f/2.8 1-5X Super Macro (the Mark II version of this lens) because the reviews I found online do not answer several of my questions about this lens. The text is not final and the page is not yet linked to the rest of my web site, but can b...
by enricosavazzi
Wed Oct 28, 2020 12:00 am
Forum: General Discussion Forum and Community Announcements
Topic: Found mantis - now what?
Replies: 4
Views: 607

Re: Found mantis - now what?

Mantodea are often kept as pets. There is quite a bit of advice on the web, for example https://www.keepinginsects.com/praying-mantis/care/ and links therein.
(at the above link, I could not resist laughing at the misspelling "live in desserts")
by enricosavazzi
Wed Oct 14, 2020 9:20 am
Forum: Equipment Discussions
Topic: Can I push the resolution of a 1:1 macro lens?
Replies: 23
Views: 2253

Re: Can I push the resolution of a 1:1 macro lens?

Lou Jost wrote:
Wed Oct 14, 2020 6:51 am
I added a short discussion and a couple of links about the other methods.

Thanks, that will be helpful to many.

I could not find the new additions, am I missing something?
Perhaps there is a server cache or something else that does not update immediately.
Clip0002a.jpg
by enricosavazzi
Wed Oct 14, 2020 6:32 am
Forum: Equipment Discussions
Topic: Can I push the resolution of a 1:1 macro lens?
Replies: 23
Views: 2253

Re: Can I push the resolution of a 1:1 macro lens?

[..]In the intro to the article, you mention two of the ways to get higher magnification out of a 1x macro lens, but you leave out what is potentially the best way, reversing it not on extension tubes but on a tube lens. I think it would be a more complete article if you mention that option and its...
by enricosavazzi
Tue Oct 13, 2020 12:24 am
Forum: Equipment Discussions
Topic: Can I push the resolution of a 1:1 macro lens?
Replies: 23
Views: 2253

Re: Can I push the resolution of a 1:1 macro lens?

As I explained above, with modern lenses that have floating elements, you should have used a teleconverter instead of extension tubes. Otherwise you aremoving the lens far from ist design point. I just published a page on my site dealing with tests of four legacy macro lenses with a 2x teleconverte...
by enricosavazzi
Sun Oct 11, 2020 7:28 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Effective aperture with teleconverter + macro lens
Replies: 6
Views: 689

Effective aperture with teleconverter + macro lens

Let's see whether I understand the problem correctly, or I am making a mistake somewhere. We assume that the pupil ratio is 1 for simplicity, so the effective aperture A' is A' = A * (m + 1) where A is the nominal aperture, and m the magnification. So if we focus a lens at m = 2 by extension alone (...
by enricosavazzi
Fri Oct 09, 2020 9:37 am
Forum: Equipment Discussions
Topic: Olympus BX stage keeps drifting down, "focus shifting".
Replies: 20
Views: 1679

Re: Olympus BX stage keeps drifting down, "focus shifting".

[...] I am using BX53 stand just to clarify, very interesting pointers about provis models, well I really like 53 because it has small footprint and does not take much space on my very busy table! [...] Indeed, the Provis stand weighs north of 50 kg "naked", needs a strong table, and most functions...
by enricosavazzi
Thu Oct 08, 2020 12:02 pm
Forum: Equipment Discussions
Topic: Olympus BX stage keeps drifting down, "focus shifting".
Replies: 20
Views: 1679

Re: Olympus BX stage keeps drifting down, "focus shifting".

The following information does not help if you already have a BX series microscope, but it is related to thermal drift so it might be interesting nonetheless. A couple of years ago, I ended up ordering an Olympus AX70 stand. It ended up being lost in the mail and eventually returned to the sender, s...
by enricosavazzi
Sun Oct 04, 2020 2:56 am
Forum: Equipment Discussions
Topic: Olympus BX stage keeps drifting down, "focus shifting".
Replies: 20
Views: 1679

Re: Olympus BX stage keeps drifting down.

Just in case, check the friction/brake on the focusing rack before you do any maintenance. This lever may be set too loose. The lever that controls friction is located between the left coarse focus knob and the stand.
by enricosavazzi
Sat Oct 03, 2020 2:01 am
Forum: Equipment Discussions
Topic: DIY Fluorescence with Zeiss fluoro condenser - help needed
Replies: 75
Views: 7806

Re: DIY Fluorescence with Zeiss fluoro condenser - help needed

This thread is already quite long, so I might be repeating some information already state above. However, here it goes: Non-stained acrylic (=Plexiglas and other names in commercial nomenclature) transmits UV well into the UVB range. Many Acrylic formulations have UV-absorbing dyes mixed in, but not...
by enricosavazzi
Tue Sep 22, 2020 12:01 am
Forum: Equipment Discussions
Topic: UV against lens fungus
Replies: 3
Views: 1037

Re: UV against lens fungus

Can UV light stop fungus growth inside objective ? The most effective wavelengths for this use are in the UVB and UVC. Most lenses (except the very few ones designed for UV imaging and a handful more) transmit little to no UVA, and no UVB and UVC, so exposing these lenses to UVB and UVC has no effe...
by enricosavazzi
Sun Sep 13, 2020 2:10 am
Forum: Equipment Discussions
Topic: Question about window on the underside of Olympus trinocular head
Replies: 25
Views: 2767

Re: Question about window on the underside of Olympus trinocular head

In a worst-case scenario, the window may have been computed as part of the optical system w.r.t. axial chromatic aberration, and removing it may increase said aberration. I have seen several examples of optical windows in Olympus infinite microscopes where a thick optical window has a thin cladding ...