[blumoon722]

Maybe I'm not understanding the problem, but I thought when attaching a camera to a spotting scope the eyepiece is removed, and the camera is attached to the scope using a T-ring adapter like this:

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[glider]

HA this is where confusion sets in , Primary focus is when attaching camera to scope ,Eye piece projection is connecting camera to eyepiece via adapter with Pentax SMC XW lense , which step down threads to 42mm x .75 TPMM in order to connect T adapter , which is specific to camera brands.
Fallow this thread and you will see a link to EP projection which has diagrams to explain . So far my understanding is to use a remote with settings on ap priority or shutter priority or manual. focus is achieved using spotting scope . In my case I do not need telephoto quality images or do I want to go down that road . with 24 MP using RAW processing there should be some good photos .
Have a look on this site which is being updated . tacticaltripod.com there is a doughnut which allows for pan I use this all the time with Phone Skope adapter getting some good pics also . problem with phone is not enough control and not enough MP I want to control FOV and speed

[Ex Finn.]

Maybe I'm not understanding the problem, but I thought when attaching a camera to a spotting scope the eyepiece is removed, and the camera is attached to the scope using a T-ring adapter like this:

Most of the time the problem is the lack of focuser travel in the spotting scope when using only the T-ring adapter.
Your camera sensor is lot further back than your eye from the focal plane of the scope. This is the case with the PF-65 and the -80
hence the need for the PF-CA35 that will shift the focal plane further back to land on the camera sensor.

[beachboy2]

Hold phone's camera over spotting scope eyepiece (there are adapters for some but not essential.) Quality can be quite good.
Costa Rica: spotting scope plus iphone 6.

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[aslyfox]

Hold phone's camera over spotting scope eyepiece (there are adapters for some but not essential.) Quality can be quite good.
Costa Rica: spotting scope plus iphone 6.

I had a guide in Yellowstone National Park do that

but you need a steady hand

[beachboy2]

Yes it needs practice and a steady hand but some scopes have a swivelling mount to take photos quickly and easily.

[hatsofe]

A related but somewhat different and older approach to "digiscoping" with Pentax spotting scopes is the use of the now discontinued Pentax PF-CA35 K-mount camera adapter. It replaces the eyepiece and allows the direct attachment of a K-mount camera (obviously without any lens) to the spotting scope. The image magnification is not as high as when using the eyepiece and an external camera but with a PF-65 scope the focal length would be 780mm with a full frame camera (K1, K1ii) attached and 1,190mm with an APS-C Pentax Camera (both at f12). I would be interested in anyones experience using the PF-CA35 adapter.

This adapter can still be found a new for sale as of today. The only matter is , accordingly to descriptions I found ,this adapter is an eyepiece itself with fixed focus (35mm focal length if I got it wright)
https://www.pentax2u.com/products/Pentax-PF-CA35-K-Mount-SLR-Camera-Adapter/525
. While the front lens element of a spotting scope is most likely an achromatic doublet (two lenses,positive and negative glued together) and this type of telephoto design was used in 1950-1970s, the rear lens element of a spotting scope is a lot more complex than a single negative lens in old telephoto design. Will this adapter improve an image quality compering to an old telephoto optics? It seems that there is no way to gather an image from just the front element alone while having a typical spotting scope structure. I acquired a few old Tokinas 500mm and 600mm and tried them out for birding. They showed decent results on APS-C, if the light was good. They both could resolve small details and exhibit good contrast at 12-20 m distance of a medium size bird. Chromatic aberration was awful though as well a halo around bright objects and required more effort to be made in post processing . It seems that in terms of the optical design (from element) they were similar to a spotting scope.
I myself am tempted to buy this Pentax scope adapter with Pentax 65ED spotting scope, but I'm afraid that the image quality will not rise above the level of old telephoto of 1970s...

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Last edited by hatsofe; 11-10-2020 at 05:27 AM.