Just did a video about how to make a hypercentric lens. It is rather easy to do, just a piece of 100mm diameter Fresnel lens with 68mm focal length. However, by itself, it is not a hypercentric lens, we need an observing lens, together to form a hypercentric lens. Actually, I was going to make a long, large headed tube to house both, but it would take a lot time to print and will be heavy, so I just left it as open cased configuration, end result is not bad.
Key points are:
1. do not use wide angle lens, instead, use a longer focal length lens as observing lens, else the effect is much less visible, even though it looks great when you observe it with naked eye Here I used Sony FE 50/f2.8 macro lens
2. make sure the Fresnel lens has long enough focal length, so you can put objects within its focal length distance.
3. the longer the separation, the stronger effect, it is amazing to see blocked object behind another (larger)one.
Here is the setup: camera with FE 50 looking down on a dice
You can see five sides of the dice . . . a typical showcase for hypercentric lens.
Looking down on a bottle. With some computation, it is possible to extract the label. However, maybe not this with Fresnel lens.
Making A Hypercentric Lens
Moderators: Chris S., Pau, Beatsy, rjlittlefield, ChrisR
Re: Making A Hypercentric Lens
Here is the setup for coins, I shot this with a US quarter and a penny so it is familiar with people. It is obvious, the quarter is much larger than the penny, yet, you can see the image of penny is much bigger than the quarter, and the penny, in normal perspective, should be blocked by the quarter, yet, with "negative perspective" that hypercentric lenses project, it is reversed.
the setup shot with hypercentric configuration
the setup shot with hypercentric configuration
Last edited by Chris S. on Tue Jan 14, 2025 8:57 pm, edited 1 time in total.
Reason: Fixed two typos
Reason: Fixed two typos
Re: Making A Hypercentric Lens
Great. Many thanks for bringing this very interesting lens combination to our attention.
Have you tried using an aspherical Fresnel lens to improve the IQ?
Have you tried using an aspherical Fresnel lens to improve the IQ?
Re: Making A Hypercentric Lens
Oh, no. I did not, anything "aspherical" sounds expensive and hard to understand :-)
I did try it with this "large" magnifying glass (80mm), the effect is less, maybe I need a different "observing" lens. IQ is better, but still suffer from all kind of optical aberrations, particularly color. I think maybe a special light source and coating to improve, but that is beyond this experiment.
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Re: Making A Hypercentric Lens
Hi,
Cool project!
if you're looking for a very large lens like that, I would suggest shopping around auction sites for the condensing optics of medium/large format enlargers.
Here's a picture I still have in my camera roll of me holding a somewhat beat up particularly obscenely sized specimen I came across in a lot of darkroom equipment I recently bought on classifieds. It's actually more than one glass element in a metalic tube, pretty easy to take apart though.
m.
Cool project!
if you're looking for a very large lens like that, I would suggest shopping around auction sites for the condensing optics of medium/large format enlargers.
Here's a picture I still have in my camera roll of me holding a somewhat beat up particularly obscenely sized specimen I came across in a lot of darkroom equipment I recently bought on classifieds. It's actually more than one glass element in a metalic tube, pretty easy to take apart though.
m.
Re: Making A Hypercentric Lens
cool! I have one for soldering station, 90mm in diameter, but no matter what I do, it won't work, at least with the FE 50/2.8 observing lens, or its focal length is too short.mightimatti wrote: ↑Wed Jan 15, 2025 2:59 pmHi,
Cool project!
if you're looking for a very large lens like that, I would suggest shopping around auction sites for the condensing optics of medium/large format enlargers.
Here's a picture I still have in my camera roll of me holding a somewhat beat up particularly obscenely sized specimen I came across in a lot of darkroom equipment I recently bought on classifieds.
condenser.jpeg
It's actually more than one glass element in a metalic tube, pretty easy to take apart though.
m.
Re: Making A Hypercentric Lens
done with magnifying glass . . . the bottom coin (Chinese penny) is similar with US penny in size, the top one (Chinese one yuan coin) is about the same size as US quarter. But, the magnifying glass has to be raised higher and the observing lens also must be raised higher, to get better effect. Else, you can barely see the effect. However, with naked eyes, it is much better as we somehow can focus on both, the bottom one is very clear with naked eyes.
Re: Making A Hypercentric Lens
Simple thin lens simulation using Ray Optics Simulation
First lens has 68mm focal length, 2nd one has 50mm, same as what I used for Fresnel experiment. The two red squares correspond to two red squares on the image side. Though on object side, the two red squares are separated by same distance as the two green squares, their images are different, the red squares on the image side have larger gap, meaning an image form by two red squares is larger than that of two yellow squares (formed by two green squares on the object side)
This concludes this experiment, happy.
First lens has 68mm focal length, 2nd one has 50mm, same as what I used for Fresnel experiment. The two red squares correspond to two red squares on the image side. Though on object side, the two red squares are separated by same distance as the two green squares, their images are different, the red squares on the image side have larger gap, meaning an image form by two red squares is larger than that of two yellow squares (formed by two green squares on the object side)
This concludes this experiment, happy.