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View Full Version here: : Moon with 150-600 Tamron .


Derek Klepp
06-03-2014, 10:23 PM
This is more a test shot as I only just got the lense today. It has a 95mm aperture as opposed to 77mm on my Canons so it will be interesting to see how it performs.Also some filaments with the Solar scope as well
Cheers Derek

Dennis
07-03-2014, 07:00 AM
That’s some impressive detail and resolution on the Moon Derek, looks like an excellent lens.:thumbsup:

Must be a beast of a lens with a 95mm aperture!:)

Cheers

Dennis

pw
07-03-2014, 07:16 AM
Aren't those measurements the filter ring size?
Isn't the aperture F5 to F6.3 depending on the focal length set?

Dennis
07-03-2014, 10:02 AM
Hi Peter

The F Ratio or F Number, is the ratio of the focal length of the lens to the effective diameter of the lens. Or, we can write:

Effective Objective Diameter = Focal Length / Focal Ratio

So, at the long end, we have a 600mm focal length with a focal ratio of F6.3 which gives an effective objective diameter of approx. 95mm.

Cheers

Dennis

pw
07-03-2014, 01:55 PM
Dennis, OK, in this instance there is minimal difference between the filter ring size and the objective size. Thanks for the explanation :-)

Derek Klepp
07-03-2014, 08:29 PM
Thanks Dennis hopefully it works out OK.

John W
09-03-2014, 10:13 AM
Hi Derek,Nice to see a lunar pic from you. Well done. Cheers, John W.