4 ms·

Kinda opposite direction, with the launch of new very high res ("50 megapixels") Sony a1 I started thinking that with a macro objective you could use it as a so

by zokier 6y ago

Kinda opposite direction, with the launch of new very high res ("50 megapixels") Sony a1 I started thinking that with a macro objective you could use it as a sort of low-magnification microscope. With a 1:1 macro, if you crop a 4k section from the full-resolution image and draw it on a 32" display you'd get 40x magnification (sort of) if I did my math right; 1px on screen would correspond to roughly 4µm which gives some ballpark on what sort features you could see with it. But it gets better still, there are at least some 2:1 magnification macro lenses [1] out there, those would double the magnification you get. I haven't really figured out how that compares to "real" microscopes, or even like the $100 chinese digital scopes. [1] https://www.dpreview.com/products/venus/lenses/venus_laowa_100_2p8_macro https://www.dpreview.com/products/venus/lenses/venus_laowa_1... and its 65mm counterpart

Scene_Cast2 6y ago
Check out Fuji's GFX100S. It's a consumer camera ($6000) that can take 400MP photos.
- throwanem 6y ago
  I bet medium-format 1:1 macro lenses are spendy, though.
  - namibj 6y ago
    Only if they're fast. Slow objectives would get by with lenses from e.g. regular eyeglasses arbitrary-aspheric production lines. It only gets expensive (>1000$) when you need fancy glass elements (or manage to waste a lot of money on inefficient R&D... computers are really good these days, and at least for fixed-focus prime lenses (you want 1:1, right?) the parameter space is fairly small. I can highly recommend [0] for some reading on how simple optics can be if you can optimize aspherics for a fixed focus. Just to state the obvious: two identical infinity-focused objectives can be placed with the infinity-corrected sides looking straight towards another, for a physically long 1:1 macro "lens". I wonder if there is a decent topology for a decently-high-NA reflective objective in the 1:1 to 1:10 (object:sensor) magnification range. And also whether some of those topologies would cope with a (sensor-sized) reflective spatial light modulator (LCoS/DLP would seem most practically relevant) in place of the sensor. I still get that mouth-watering imagination when thinking about direct digital (maskless) photolithography, as the flexibility is enormous, especially regarding rapid prototyping of highly integrated circuits (350 nm is the limit for single-patterning using aluminium-coated MEMS modulators (aka TI's DLP technology), due to the UV reflectivity drop below 400 nm and thermal limits of the MEMS device). [0]: https://www.telescope-optics.net/ https://www.telescope-optics.net/
    - jimduk 6y ago
      The back to back infinity-focussed objective set up works nicely with 2 sets of cheap infinity microscope objectives 2x or 4x back to back in a thorlabs tube. Paired lenses cancel out a lot of aberrations (but not all of them). I use this setup regularly for fairly close up, highly planar projective work. For 'low magnifications' say 2:1 and up the Edmunds 2X, 0.15 NA, Ultra Compact Objective has decent price/performance, but this is for sensors in the 1/1.8 - 1" range. If you come up with a nice, planar, cheapish 1:1 design for large sensors, drop me a line. (Disclaimer - not an optics person, but peered into the fascinating rabbit hole)
      - namibj 6y ago
        What numerical aperture and image circle are we talking about? 0.15 NA leaves a lot on the table (at least 0.6 NA objectives can be had for still-decent prices). But I'd probably look at a Zeiss Planar style design. In general, a 3/5-element design (achromat/apochromat) should do the trick I think, provided you have access to arbitrary aspherics. And in case you can accept a shift in focal length with wavelength (like monochromatic photolithography would), a single symmetric element should be up to the task, unless I'm missing something.
        jimduk 6y ago
        Thanks, we are pretty low budget. Image circles are in the 1/3", 2/3" range and we are looking at patterns with say 5 to 50 um pitch on a flat planar object, monochromatic, we control illumination, standard 3.45 um pixels (so 1k to 5kish). We have a decent small design with two elements (good planarity, ok resolving and ok ish depth of field are what we care about). But we also sometimes look at larger frame (aps-c and up) and are also interested in smaller (eg VGA Omnivision type tiny module but with a decent planar macro lens e.g. f= 4 or 6mm, for 0.5 or 1x mag would be interesting). We do imager based metrology at the sub um and nm level
        namibj 6y ago
        Yeah, sounds like a normal https://en.wikipedia.org/wiki/Double-Gauss_lens https://en.wikipedia.org/wiki/Double-Gauss_lens from BK7 or so should do the trick. You'd have significant chromatic abberation, but with monochromatic illumination that's not a problem. This would just be 4 normal lenses, afaik. And you should be able to reach around 100 mm image circle I guess with the low NA you get away with at that relatively low resolution.
- LegitShady 6y ago
  >It's a consumer camera ($6000) very few consumers spend $6k on a camera, and if I spent $6k on a camera I wouldn't want it to be consumer.
  - sudosysgen 6y ago
    To be fair, in photography nowadays, the line between professional and consumer is veeeryy thin. I'm a hobbyist and spent 600$ on my camera, just a few years ago it was used by quite a few professionals.
    - LegitShady 6y ago
      I spent some money on my 50d a long time ago, and its still a great camera. Then I spent thousands on EF lenses instead and those lenses will move to a 5d2 or whatever used body I find to replace the 50d.
      - namibj 6y ago
        Just curious: these are (mostly, weighted by cost) zoom lenses, right? Or did you invest a lot into very fast prime lenses?
        LegitShady 6y ago
        I think fast primes are amazing but not convenient. My lens collection currently looks like this: Canon 50mm f/1.8 (because its fun and cheap) Canon 17-40mm f4/L Sigma 17-55mm f/2.8 Canon 70-200 f/2.8 L Canon 100mm f/2.8L Macro You can cover quite a bit of range with the 17-55 and 70-200 in just two lenses. I also have the original Canon EOS M with the 20mm pancake lense (which is super old at this point) with an adapter to stick EF lenses on it. When I upgrade to an actual full frame body (my 50d is an APS-C size sensor) I'll probably want to see how zoomed 200mm feels but until then I'm pretty happy. I still do a fair amount of hobby photography but it's one of a dozen hobbies so they probably don't get as much attention as they should.
    - AuryGlenz 6y ago
throwanem 6y ago
Scaling up a crop doesn't really increase magnification at all, though. You're still limited by sensor resolution and reproduction ratio. Scaling up the result lets you see it from further away, but it doesn't add information that the sensor didn't capture. Whatever the reproduction ratio of the lens at the focal length you're using, that's going to determine the minimum feature size you'll be able to resolve. I have some wasp shots [1] that I took at or near 1:1 on an APS-C (Nikon DX) sensor, and I had three of them printed and framed at 36"x24" to hang as a triptych across one of my living room walls. [2] They're gorgeous at that size, but they're not sharper at that size, you know? [1] https://aaron-m.com/2019/07/08/polistes-metricus https://aaron-m.com/2019/07/08/polistes-metricus [2] Yes, I live alone, why do you ask? :) I originally had the middle one over my bed, but my boyfriend at the time found it offputting. Can't imagine why...
formerly_proven 6y ago
Many wide-angle lenses are amenable to reverse mounting, which gives typical magnifications of around 5x or higher. Also, the working distance is almost constant (about the flange distance, so ~40-something mm for SLR lenses) across the range of magnifications, unlike macro lenses where adding extension continually reduces working distance until it gets zero/negative.

by zokier 6y ago

Scene_Cast2 6y ago

Check out Fuji's GFX100S. It's a consumer camera ($6000) that can take 400MP photos.

throwanem 6y ago
I bet medium-format 1:1 macro lenses are spendy, though.
- namibj 6y ago
  Only if they're fast. Slow objectives would get by with lenses from e.g. regular eyeglasses arbitrary-aspheric production lines. It only gets expensive (>1000$) when you need fancy glass elements (or manage to waste a lot of money on inefficient R&D... computers are really good these days, and at least for fixed-focus prime lenses (you want 1:1, right?) the parameter space is fairly small. I can highly recommend [0] for some reading on how simple optics can be if you can optimize aspherics for a fixed focus. Just to state the obvious: two identical infinity-focused objectives can be placed with the infinity-corrected sides looking straight towards another, for a physically long 1:1 macro "lens". I wonder if there is a decent topology for a decently-high-NA reflective objective in the 1:1 to 1:10 (object:sensor) magnification range. And also whether some of those topologies would cope with a (sensor-sized) reflective spatial light modulator (LCoS/DLP would seem most practically relevant) in place of the sensor. I still get that mouth-watering imagination when thinking about direct digital (maskless) photolithography, as the flexibility is enormous, especially regarding rapid prototyping of highly integrated circuits (350 nm is the limit for single-patterning using aluminium-coated MEMS modulators (aka TI's DLP technology), due to the UV reflectivity drop below 400 nm and thermal limits of the MEMS device). [0]: https://www.telescope-optics.net/ https://www.telescope-optics.net/
  - jimduk 6y ago
    The back to back infinity-focussed objective set up works nicely with 2 sets of cheap infinity microscope objectives 2x or 4x back to back in a thorlabs tube. Paired lenses cancel out a lot of aberrations (but not all of them). I use this setup regularly for fairly close up, highly planar projective work. For 'low magnifications' say 2:1 and up the Edmunds 2X, 0.15 NA, Ultra Compact Objective has decent price/performance, but this is for sensors in the 1/1.8 - 1" range. If you come up with a nice, planar, cheapish 1:1 design for large sensors, drop me a line. (Disclaimer - not an optics person, but peered into the fascinating rabbit hole)
    - namibj 6y ago
      What numerical aperture and image circle are we talking about? 0.15 NA leaves a lot on the table (at least 0.6 NA objectives can be had for still-decent prices). But I'd probably look at a Zeiss Planar style design. In general, a 3/5-element design (achromat/apochromat) should do the trick I think, provided you have access to arbitrary aspherics. And in case you can accept a shift in focal length with wavelength (like monochromatic photolithography would), a single symmetric element should be up to the task, unless I'm missing something.
      - jimduk 6y ago
        Thanks, we are pretty low budget. Image circles are in the 1/3", 2/3" range and we are looking at patterns with say 5 to 50 um pitch on a flat planar object, monochromatic, we control illumination, standard 3.45 um pixels (so 1k to 5kish). We have a decent small design with two elements (good planarity, ok resolving and ok ish depth of field are what we care about). But we also sometimes look at larger frame (aps-c and up) and are also interested in smaller (eg VGA Omnivision type tiny module but with a decent planar macro lens e.g. f= 4 or 6mm, for 0.5 or 1x mag would be interesting). We do imager based metrology at the sub um and nm level
        namibj 6y ago
        Yeah, sounds like a normal https://en.wikipedia.org/wiki/Double-Gauss_lens https://en.wikipedia.org/wiki/Double-Gauss_lens from BK7 or so should do the trick. You'd have significant chromatic abberation, but with monochromatic illumination that's not a problem. This would just be 4 normal lenses, afaik. And you should be able to reach around 100 mm image circle I guess with the low NA you get away with at that relatively low resolution.
LegitShady 6y ago
>It's a consumer camera ($6000) very few consumers spend $6k on a camera, and if I spent $6k on a camera I wouldn't want it to be consumer.
- sudosysgen 6y ago
  To be fair, in photography nowadays, the line between professional and consumer is veeeryy thin. I'm a hobbyist and spent 600$ on my camera, just a few years ago it was used by quite a few professionals.
  - LegitShady 6y ago
    I spent some money on my 50d a long time ago, and its still a great camera. Then I spent thousands on EF lenses instead and those lenses will move to a 5d2 or whatever used body I find to replace the 50d.
    - namibj 6y ago
      Just curious: these are (mostly, weighted by cost) zoom lenses, right? Or did you invest a lot into very fast prime lenses?
      - LegitShady 6y ago
        I think fast primes are amazing but not convenient. My lens collection currently looks like this: Canon 50mm f/1.8 (because its fun and cheap) Canon 17-40mm f4/L Sigma 17-55mm f/2.8 Canon 70-200 f/2.8 L Canon 100mm f/2.8L Macro You can cover quite a bit of range with the 17-55 and 70-200 in just two lenses. I also have the original Canon EOS M with the 20mm pancake lense (which is super old at this point) with an adapter to stick EF lenses on it. When I upgrade to an actual full frame body (my 50d is an APS-C size sensor) I'll probably want to see how zoomed 200mm feels but until then I'm pretty happy. I still do a fair amount of hobby photography but it's one of a dozen hobbies so they probably don't get as much attention as they should.
  - AuryGlenz 6y ago

throwanem 6y ago

Scaling up a crop doesn't really increase magnification at all, though. You're still limited by sensor resolution and reproduction ratio. Scaling up the result lets you see it from further away, but it doesn't add information that the sensor didn't capture. Whatever the reproduction ratio of the lens at the focal length you're using, that's going to determine the minimum feature size you'll be able to resolve. I have some wasp shots [1] that I took at or near 1:1 on an APS-C (Nikon DX) sensor, and I had three of them printed and framed at 36"x24" to hang as a triptych across one of my living room walls. [2] They're gorgeous at that size, but they're not sharper at that size, you know? [1] https://aaron-m.com/2019/07/08/polistes-metricus https://aaron-m.com/2019/07/08/polistes-metricus [2] Yes, I live alone, why do you ask? :) I originally had the middle one over my bed, but my boyfriend at the time found it offputting. Can't imagine why...

formerly_proven 6y ago

Many wide-angle lenses are amenable to reverse mounting, which gives typical magnifications of around 5x or higher. Also, the working distance is almost constant (about the flange distance, so ~40-something mm for SLR lenses) across the range of magnifications, unlike macro lenses where adding extension continually reduces working distance until it gets zero/negative.