Powermate question?

[northcanadian]

Hi all:

Will a powermate generally allow more light to the camera than a barlow...?  Been curious about this lately.

Thanks again

Cheers

Roger

[ronin]

Considering that there is likely just a 1% loss at each air/glass interface, possibly less, you likely could not tell, and there are not that many interfaces.

I would guess the powermate has more glass but better coatings, just to add more confusion.

[jambouk]

We've had a discussion about this before, so do have a search for power mate using the search function.

My understanding is that the benefits of the power mate is they introduce less aberration of the image than a barlow, produce a sharper image across the full width of the field of view and not just at the centre, and less vignetting.

I think also the power mate has more optical elements in than a standard barlow, and as each optical element reduces light transmission, it is possible that technically a power mate passes fewer photons rhan a barlow. But i don't know what optical coatings are used in a power mate compared to a barlow, and the other benefits of a power mate mean any loss of photons isn't noticed and the other benefits outweigh this anyway.

Depends what you are using it for, and how good your eyes are I guess.

James

[jambouk]

Ah, seems ronin has been much quicker at typing and more succinct than me!

James