Sunex, 185° SuperFisheye 5.6mm F/5.6

[dabateman]

Just found a super cheap add on lens that for some reason ended up buying. Its a Phoenix 0.25x fisheye adapter. Might be total trash. But it screws on the front of a lens with 52mm thread. So mounting filters will be easy. Some reviews of it were very positive. Still a couple on the bay for $10. So see if I lost out.

I am not expecting much. But it might work, I have a bunch of m43rds or even fused silica lenses to test it with. So it will be the UV limiting factor. Seems to only have 3 elements in 3 groups.

[nfoto]

My experience with such "screw-in" fisheye adapters is not stellar, to put it mildly. They might appear to transmit a lot of UV due to simple optics and inefficient coating (if at all) - however, due probably to the very same factors they also introduce loss of sharpness and lots of chromatic errors for UV imaging. The only useful converter has been an Olympus fisheye for underwater usage (on my Nikon AW1 + 10mm), but then this is strictly for visible light applications.

 

Your mileage may vary so hope for the best.

[ulf]

Back to the main topic please!

My fault.

I should not have baited with comments about other lenses.

 

Added Manufacturer- and S/N-lines in the information digest at the top

Changed the Simplified transmission metric parameter UV_{HC to} UV_HalfC to make it more clear.

Added a comment about the Canon EF mount.

Tweaked and improved the sentence about rear mounting filters.

Corrected language where I found it incorrect or unclear.

[Andrea B.]

Ulf, I will review as promised tomorrow.

A.//

[Andrea B.]

OK, I have read through the post. It is looking good.

 

I have some suggestions, but let me think about that a bit more before writing more of them here.

For example, include the front filter thread type and diameter. (Ignore. I see where you have that. It was just that the Sunex has no front filter capability.)

 

A simple test for chromatic abberation should definitely be included as most lenses we use for UV are not corrected for this because they were never intended for use in the UV range. Jonathan's slanted ruler test is a good one. Also the crumpled aluminum foil test is useful.

 

As someone mentioned above, there are only about 3 or 4 people who can analyze a lens in this much detail. But for anyone wanting to put in the work, then it would be wonderful to have your lens info. We can definitely provide a section for this. I would probably makeover the Lens Gallery.

[dabateman]

Well I didn't get that 52mm fisheye adapter. The seller over counted, so was refunded. I did end up getting a really cheap Nikon mount Sigma 4.5mm which I might test as listed here. I am curious how it performs in UV.

[ulf]

I have a Sigma 4.5mm in Canon EF mount that I eventually can test the same way as the Sunex.

[nfoto]

Well I didn't get that 52mm fisheye adapter. The seller over counted, so was refunded. I did end up getting a really cheap Nikon mount Sigma 4.5mm which I might test as listed here. I am curious how

it performs in UV.

 

Don't hold your breath in anticipation of any UV response.

[ulf]

Don't hold your breath in anticipation of any UV response.

No, that would be lethal.

[dabateman]

No, that would be lethal.

 

Both ways. UV can be lethal. Fortunately we just pass out from holding our breathe and usually wake up.

[dabateman]

I scanned the Sigma 4.5mm in Nikon mount. The UV cut off is about 375nm. But very shallow curve into UV.

So a 390bp filter might be best, if you are trying. My Fujinon 2.7mm f1.8 was much better into UV. But it can't take filters. so can't easily be used.

I also have an experimental 160 degree lens with cut off at 380nm. But it can only take gel filters. will have to see if I can take a filter to the front.