brucew29 Loc: Cincinnati, Ohio

If you use Prime Focus with your scope and camera and print full frame, your 35mm equivalent zoom factor for the print would be equal to the focal length of the scope multiplied by your camera sensor factor and then divided by 50 which is the standard lens for 35mm camera more or less. By cropping the print image, you will effectively be increasing the zoom factor more depending on the crop amount.

If you use a Barlow lens with camera and scope then the effective zoom will be increased by the Barlow factor... using two TCs with my camera and lens would be similar to using two piggybacked Barlow lens with your scope...

P.S. If you have a 2,000 mm focal length scope and use a 1.6x camera sensor factor, that would be equal to 1.6 x 2,000 mm or 3,200mm. If you use a 2.0x Barlow then that would be... 2 x 3,200mm = 6,400mm. if you do a print crop with a factor of 2x then that would be 2 x 6,400mm or 12,800mm... or 12,800/50 = 256x zoom... :)

CraigFair Loc: Santa Maria, CA.

I use a full frame camera which would give me a 4000mm with the 2x.
And not quite sure what my 17mm scope lens as Eyepiece Projection would be. I lost the formula for Eyepiece Projection.
Found it 2000/17=118x
Craig

brucew29 Loc: Cincinnati, Ohio

:thumbup:

brucew29 Loc: Cincinnati, Ohio

Thanks northcoast42... much appreciated...

Fullframe Loc: Bucks County, Pennsylvania

Wow! :thumbup: Can you imagine if Galileo had the Tamron? :shock:

brucew29 Loc: Cincinnati, Ohio

Thanks Fullframe... much appreciated... in case you didn't see my calcs for my Moon shot here they are...

TCs (1.4X)x( 2.0X) = 2.8X; 2.8 x 600 mm = 1,680 mm
Camera Sensor crop factor = 1.6X; (1.6)x(1,680 mm) = 2,688 mm
Print Crop Factor = 2.88X per Photofiltre (software program)...
Total Combined Effective Focal Length = 2.88 x 2,688 mm = 7,471 mm!!!

Comparative 35 mm Camera with standard 50 mm lens would calculate as follows...

7,471/50mm = 149.42X Zoom... if my math is correct... looking at the Download View would seem to put my calcs in the ballpark... more or less...

When the weather gets better and I get a clear shot of the Moon again, I'll have a new experimental setup to try out so stay tuned in for a future update... and I see that you also have the Tamron 150-600mm lens... it has been great lens for me as you can see by my Moon shots...