Would you consider this lens (Samyang 8mm CS II) defective?

Question

I purchased a new Samyang 8mm F3.5 UMC Fish-eye CS II today. After I made  my first shot with it I  immediately noticed a flaw. At f/3.5 the flare of bright objects is shifted towards the bottom (and just a little to the left).
I have quite few lenses and have never seen such a thing, Only my old Revuenon 1.4/50mm does it but in very subtle way. The flare is shifted to the left and it is barely noticeable, in fact I noticed it after purchasing  the Samyang, and the effect is negligible (just few pixels difference).
The lens is usable after f/5 and flare seems completely disappear at f/5.6 which effectively makes the lens at best f/5 8mm.
I don't mind flares, as long as they are even around the object, but such flares make photos just ugly.
Is this effect considered normal?
Here are photos made with normal position of camera and rotated. The camera is Pentax K5.

Qeeet · Accepted Answer

After returning that lens and buying the new one, I can conclude with confidence that the first lens was definitely defective.
This new lens is not perfect either, but it performs much better. You can see those ghosting flares are going up and a bit to left, but the effect is less noticeable.
The focus on both images is the best I could get - at infinity.
Finally, the lens is usable at f/3.5.
The images are cropped.

Would you consider this lens (Samyang 8mm CS II) defective?

One Answer

Add your own answers!

Ask a Question