Search found 1488 matches

by enricosavazzi
Thu Mar 30, 2023 4:55 am
Forum: Equipment Exchange
Topic: ** Sold ** : Oshiro 60 mm f/2.8 2x macro lens
Replies: 0
Views: 915

** Sold ** : Oshiro 60 mm f/2.8 2x macro lens

The Oshiro is one of the first macro lenses focusing between infinity and 2x. It came out immediately after the Laowa 60 mm f/2.8 lens and was even advertised with pictures of the Laowa lens, but it is, and looks, slightly different, optically as well as mechanically. I reviewed and tested this spec...
by enricosavazzi
Thu Mar 30, 2023 4:51 am
Forum: Equipment Exchange
Topic: ** Sold **: Laowa 60 mm 2x macro
Replies: 0
Views: 919

** Sold **: Laowa 60 mm 2x macro

The Laowa is one of the first macro lenses focusing between infinity and 2x. I reviewed and tested this specimen of the Laowa 60 mm https://www.savazzi.net/photography/60mm-2x-lenses.html and https://www.savazzi.net/photography/laowa-oshiro-test.html . Note that these pages describe two lenses, Laow...
by enricosavazzi
Thu Mar 30, 2023 3:29 am
Forum: Equipment Exchange
Topic: ** Sold **: Zhongyi Mitakon Creator Apo 85 mm f/2.8 1x-5x Super Macro
Replies: 0
Views: 880

** Sold **: Zhongyi Mitakon Creator Apo 85 mm f/2.8 1x-5x Super Macro

The Zhongyi 1x-5x Super Macro is one of few lenses (two, if I remember correctly) with a continuous magnification range of 1x to 5x. This specimen is the revised version of the lens with a smaller front element, after the initial version of the lens with a wider front element was pulled from the mar...
by enricosavazzi
Wed Mar 29, 2023 11:04 am
Forum: General Discussion Forum and Community Announcements
Topic: MTF Mapper target help needed
Replies: 16
Views: 5986

Re: MTF Mapper target help needed

OK, there are several different definitions of contrast, but what most of them have in common is that contrast is defined, and adjusted, relative to some kind of average luminance value. See e.g. https://en.wikipedia.org/wiki/Contrast_(vision) . I think what you are talking about in your example is ...
by enricosavazzi
Wed Mar 29, 2023 8:05 am
Forum: General Discussion Forum and Community Announcements
Topic: MTF Mapper target help needed
Replies: 16
Views: 5986

Re: MTF Mapper target help needed

Yes, it is surprising. I would expect different and lower values for the pictures where the contrast is lower, in your example the bottom pictures. My understanding - maybe this is not the right word - lets say assumption is that this and similar programs are looking for an edge and then count the ...
by enricosavazzi
Wed Mar 29, 2023 2:42 am
Forum: Equipment Discussions
Topic: Flash vs Continuous lighting
Replies: 18
Views: 2825

Re: Flash vs Continuous lighting

[...]If you have a 100ws strobe and a 100ws continuous light all things being equal they will give you the same level of subject illumination, so let’s say at iso 100 with the strobe on full power I need F8 to get a correct exposure, shutter at 1/250, now I switch the strobe for a 100w continuous l...
by enricosavazzi
Wed Mar 29, 2023 1:58 am
Forum: General Discussion Forum and Community Announcements
Topic: MTF Mapper target help needed
Replies: 16
Views: 5986

Re: MTF Mapper target help needed

One thing I wonder about software for computing/measuring MTF is that the calculations are designed for optics, but seem to ignore the discrete pixel structure of sensors. The MTF graphs from all software packages I tried so far (not so many, so perhaps not a representative sample) span the MTF rang...
by enricosavazzi
Wed Mar 29, 2023 12:35 am
Forum: General Discussion Forum and Community Announcements
Topic: MTF Mapper target help needed
Replies: 16
Views: 5986

Re: MTF Mapper target help needed

Also a thing that may not be immediately obvious, is that to combine the MTF of different elements in the imaging chain from subject to image, you multiply their MTF. Say for example that you have a lens that gives you 80% MTF at a given lp/mm and a camera that gives you 60% MTF at the same lp/mm. T...
by enricosavazzi
Mon Mar 27, 2023 6:52 am
Forum: Equipment Discussions
Topic: Carl Zeiss Universal Microscope 1st Edition
Replies: 13
Views: 1660

Re: Carl Zeiss Universal Microscope 1st Edition

[...]I would like to know what the two levers on the side of the light tube are for ?[...] Yours is complete with most of the illuminator. I never had one like this, but my first guess would be that one of the levers controls a diaphragm of the illuminator to adjust the diameter of the light beam. ...
by enricosavazzi
Sun Mar 26, 2023 2:22 am
Forum: General Discussion Forum and Community Announcements
Topic: MTF Mapper target help needed
Replies: 16
Views: 5986

Re: MTF Mapper target help needed

I am also rather new to making my own MTF tests, so my understanding of MTF software and their results may be wrong in some respects. I don't get paid to do lens tests. They are only for my information. So there are relatively strict limits to what I am willing to pay for test equipment and software...
by enricosavazzi
Thu Mar 23, 2023 12:57 am
Forum: Equipment Discussions
Topic: Stackshot shutter cable for Sony
Replies: 14
Views: 1704

Re: Stackshot shutter cable for Sony

Like others mentioned, the easiest way is to buy a ready-made short spiral cable from Amazon, which carries at one end a Micro USB plug and at the other end a 2.5 mm stereo jack. For an example search on Amazon "JJC Shutter Release Connector Cable For Sony" but there are also others. Then connect it...
by enricosavazzi
Sat Mar 18, 2023 8:59 am
Forum: Equipment Discussions
Topic: Carl Zeiss Universal Microscope 1st Edition
Replies: 13
Views: 1660

Re: Carl Zeiss Universal Microscope 1st Edition

Thanks very much Enrico You know me from the UVP forum. Hi Colin, yes, I recognized your "callsign". This is exactly what I was wanting to know. I have purchased the Epi-Illumination turret & nosepiece for the 1st edition & I am hoping to adapt it to my M42 tube connection to my full frame camera. ...
by enricosavazzi
Sat Mar 18, 2023 3:19 am
Forum: Equipment Discussions
Topic: Carl Zeiss Universal Microscope 1st Edition
Replies: 13
Views: 1660

Re: Carl Zeiss Universal Microscope 1st Edition

I am looking for information on the Carl Zeiss Universal Microscope 1st Edition please ? Is there a product description &/or manual on-line ? I would like to know if the objectives are finite or infinity ? I don't know if it helps, but you can look at this: https://www.savazzi.net/download/Zeiss_Un...
by enricosavazzi
Tue Mar 14, 2023 6:52 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: How can I mount a focusing rail to make it more stable?
Replies: 5
Views: 2423

Re: How can I mount a focusing rail to make it more stable?

If you are equipped to make some mechanical modifications involving drilling and tapping, there are additional improvements to consider. One is that the lowermost slider and rack of the Nikon bellows are no longer necessary if you mount the bellows on a separate focusing rail. The nylon inserts of t...
by enricosavazzi
Fri Mar 10, 2023 1:08 pm
Forum: General Discussion Forum and Community Announcements
Topic: UV photography box. Of interest for discussion of sources.
Replies: 11
Views: 4677

Re: UV photography box. Of interest for discussion of sources.

https://www.instructables.com/Build-a-Simple-UV-Photography-Box/ N.B. there's a Download option. Strictly speaking, this in not UV photography. It is photography of UV-excited fluorescence in the visible range. Different UV wavelengths stimulate the emission of different VIS wavelengths in differen...