Has anyone used a system such as the one shown in this link? If so, what are you thoughts about it? http://www.qioptiq.com/optem-fusion-lens
Marci
Optem fusion
Moderators: Chris S., Pau, Beatsy, rjlittlefield, ChrisR
-
rjlittlefield
- Site Admin
- Posts: 24432
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
I have not had hands-on experience with one of those systems. Based on feedback that I've received from other people, I would summarize that there is generally a spectrum from image quality to operational convenience and these systems are designed to emphasize convenience.
Take a look, for example, at the final page of their BROCHURE. There, the "maximum configuration" 7:1 zoom system quotes NA=0.047 over a 5.2x3.9mm field, and NA=0.16 over a 0.76 x 0.57 mm field, both with 32 mm working distance. Using conventional non-zoom optics and swapping in appropriate objectives, the corresponding values would be NA=0.10 or more over the larger field (using a 4X or 5X objective), and NA=0.40 over the smaller field (using a 20X objective).
NA correlates directly with resolution, so you can see that the Optem specs imply something like half the resolution of swap 'em out optics applied to the same subjects.
In exchange, you get the whole range at the twist of a zoom ring, plus the greater working distance and DOF that goes along with lower NA.
--Rik
Take a look, for example, at the final page of their BROCHURE. There, the "maximum configuration" 7:1 zoom system quotes NA=0.047 over a 5.2x3.9mm field, and NA=0.16 over a 0.76 x 0.57 mm field, both with 32 mm working distance. Using conventional non-zoom optics and swapping in appropriate objectives, the corresponding values would be NA=0.10 or more over the larger field (using a 4X or 5X objective), and NA=0.40 over the smaller field (using a 20X objective).
NA correlates directly with resolution, so you can see that the Optem specs imply something like half the resolution of swap 'em out optics applied to the same subjects.
In exchange, you get the whole range at the twist of a zoom ring, plus the greater working distance and DOF that goes along with lower NA.
--Rik
-
enricosavazzi
- Posts: 1568
- Joined: Sat Nov 21, 2009 2:41 pm
- Location: Västerås, Sweden
- Contact:
I have an Optem Zoom 70 (an older model) and other similar industrial zoom objectives:
http://savazzi.net/photography/photomacrolenses4.htm
My initial tests essentially confirmed that they are made with small-sensor videocameras in mind (i.e., small image circles and resolution lower than we are used to with digital cameras). There are accessory optics to enlarge the image circle, but they can do nothing about image quality. There are also accessories for mounting infinity objectives at the front of these zooms and use the zoom as a tube lens (kind of), but results are only acceptable with ordinary inspection videocameras.
If you lump into this category also the Leica Apozoom/Macrozoom and the Zeiss Tessovar,
http://savazzi.net/photography/wild_leica_m420.htm
http://savazzi.net/photography/tessovar.htm
they give better results because they provide wider effective apertures, but still more limited than fixed-focal-length photomacrographic lenses and microscope objectives often used in this group.
http://savazzi.net/photography/photomacrolenses4.htm
My initial tests essentially confirmed that they are made with small-sensor videocameras in mind (i.e., small image circles and resolution lower than we are used to with digital cameras). There are accessory optics to enlarge the image circle, but they can do nothing about image quality. There are also accessories for mounting infinity objectives at the front of these zooms and use the zoom as a tube lens (kind of), but results are only acceptable with ordinary inspection videocameras.
If you lump into this category also the Leica Apozoom/Macrozoom and the Zeiss Tessovar,
http://savazzi.net/photography/wild_leica_m420.htm
http://savazzi.net/photography/tessovar.htm
they give better results because they provide wider effective apertures, but still more limited than fixed-focal-length photomacrographic lenses and microscope objectives often used in this group.
--ES
-
ray_parkhurst
- Posts: 3690
- Joined: Sat Nov 20, 2010 10:40 am
- Location: Santa Clara, CA, USA
- Contact:
These systems are similar to the Bausch & Lomb MonoZoom-7 system that I am very familiar with. I also have a similar system from Meiji. All were designed for optical inspection / machine vision / industrial applications, where very long working distances plus decent but not outstanding image quality were required. They are excellent for their intended purpose, and in the past I have even used them successfully for photomacrography, but they are not hard to beat with inexpensive microscope objectives.