How much did you have to spend to bribe your kids to pose? Mine now demands a new cell phone.
How much did you have to spend to bribe your kids to pose? Mine now demands a new cell phone.
I would love to find 2 identical achromats with a 2000mm focal lenght or +0,5 diopters... in a 77mm or more diameter... i really want to make a 1000mm lens...
Weirdly, so do I! I want to shoot the moon in 4x5. Let me know if you find them somewhere.
if you use a +1 diopter only you will have a 1000mm.... but i´m trying to make a steinheil periskop... not a chevalier achromat... nor a meniscus wollaston...
You will find it one day. I think http://www.surplusshed.com/ had them at one point.
Originally Posted by ruilourosa
I would love to find 2 identical achromats with a 2000mm focal lenght or +0,5 diopters... in a 77mm or more diameter... i really want to make a 1000mm lens...
This was made with a +3 closeup lens with the back of a film canister as the aperture and a Packard shutter...
Should be f/32, but this was shot at f/22 as an 8x10 Paper Negative.
The biggest practical problem with this lens is focussing.
Things are pretty blurry with the aperture off, and pretty dim with the aperture on...
Thats why you should use an aperture cutout like f9 or f11, compromise, for focusing =)
Yeah, good point. I start looking for some nice round "thing", and I'll make a middle value aperture.
I'd recommend focusing at the taking aperture. Much of the charm of these lenses comes from spherical aberration, which goes hand-in-hand with focus shift when stopping down the aperture.
"I love my Verito lens, but I always have to sharpen everything in Photoshop..."
Don't the lenses for eyeglasses begin as large (about 3 inches diameter) round blanks that are ground in a lab to fit the eyeglass frames? If so, your local optometrist may be able to order various diopter blanks and have the lab grind them to desired diameter.
As an eyeglass wearer, I should have thought of this long ago.
Keith
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