exit pupil is not round

[Avinash]

i have recently purchased an olympus 10*50 DPS-I binocular. while using them i noticed that the exit pupil are not perfectly round but have a slight distortion in shape. i looks like a circle has been pushed a little inwards on one side. is this error acceptable?

Should i return the product and request for an exchange?

-beginner

it looks like in the image.

[Stargazer_00]

I think that's one of the prisms encroaching on the light path.

In terms of returning them, you have to ask yourself how much did you pay for them and how much do you want the hassle of returning them to potentially get the same again, or worse?

I've had a number of sub £100 bins with this and I never really saw it have any effect at the eyepiece.

I guess ask yourself, are you satisfied with the view?  If so, keep them.

[ChrisLX200]

This is often found on budget binos, the prisms are a little undersize and not able to reflect the whole of the light beam. It's one of the first tests you do when looking at binoculars. The actual % light loss will be small however so other factors may sway you to still find them acceptable. Check for abberations (chromatic, field) and see if they perform acceptably.

ChrisH

[Langy]

These are supposed to be good budget binos, I'm still toying with hitting that Buy button to get a pair myself.

A lot of people rate these for their price where you don't want to spend near to three figures or more.

[ChrisLX200]

The slightly clipped lightpath would not be a deal breaker for me, although it would make me look a bit more closely at the overall contruction. Of more importance is the quality of the other optical components and how well they perform. Many budget binos do not perform well on the night sky simply because it's the most severe of tests and the binos were never designed for it. On terrestrial subjects many of the defects would be invisible. Only in the highest quality products can you expect (near) perfection in this respect, and that is probably accidental unless specifically designed and produced for astro use. Beyond that, only testing lots of different pairs with an experienced eye will get you the best performance at a bargain price. I tested a pair of Leica 10x50s once and despite their very high asking price found them inferior to my Minoltas for night time use on the stars. I own two pairs of standard binos the Minolta 10x50 (porror prism) and Pentax 8x42 DCF HRc. Of the two the Minolta 10x50 are better, but the Pentax are not far behind (and are exceptional for roof prism binos). Although these might be classed as 'very good' optically they are still full of defects and compromises to the experienced eye.

ChrisH