Moon with 150-600 Tamron .

[Derek Klepp]

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]

That’s some impressive detail and resolution on the Moon Derek, looks like an excellent lens.

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

Cheers

Dennis

[pw (Peter)]

Aren't those measurements the filter ring size?
Isn't the aperture F5 to F6.3 depending on the focal length set?

[Dennis]

Originally Posted by pw

Aren't those measurements the filter ring size?
Isn't the aperture F5 to F6.3 depending on the focal length set?

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 (Peter)]

Dennis, OK, in this instance there is minimal difference between the filter ring size and the objective size. Thanks for the explanation :-)

[Derek Klepp]

Thanks Dennis hopefully it works out OK.

[John W (John Wilkinson)]

Hi Derek,Nice to see a lunar pic from you. Well done. Cheers, John W.