jvc1
Senior Member
I've been wanting an ultra wide lens for my APS-C Canon 90d and found the Opteka 6.5mm f/3.5 lens on sale for $140 USD. and decided to give it a try. This is a manual APS-C lens with a 180 deg. diagonal field of view.
The build quality is quite good, metal mount and barrel with a large, smooth operating rubber focus ring. The aperture ring has fixed stops at f/3.5 and f/5.6 then every 1/2 stop to f/22. Another fixed position between f/3.5 and f/5.6 would have been nice however there is room to position the ring between these stops but you don't know exactly what your getting. The hood can be removed but you need it in place to install the cap.
This is a manual focus lens, the depth of field is so deep that even at f/3.5, if you use the distance scale to pick the approximate critical spot you'll be good. The MFD of this lens is 11.8 inches presenting some interesting possibilities. Focusing at the MFD gets a little more difficult if you want the sharpest possible images. Live view X 10 helps for this.
Image quality. Wide open, images are pretty soft in the center and a little softer as you move towards the edges. Sharpness improves a lot at f/5.6. Depending on the lighting, there's a lot of CA at f/3.5, this too improves at f/5.6 but is still visible in the 2 images below.
This one is at f/3.5, nothing is all that sharp and there's heavy CA, especially in the branches in the upper right. (SOOC JPEG)
This one is at f/5.6, the sharpness improves a good bit and the CA is less obvious but still there. (SOOC JPEG)
Just had to do the brick wall, these are at the MFD.
This one @f/3.5, not all that sharp. (SOOC JPEG)
This one at f/5.6, the sharpness improves a lot. (SOOC JPEG)
The color and contrast very closely match the actual scenes.
My conclusion is that if you're a pixel peeping addict who just can't let it go in ultra wide images you may want to pass. If though, you want an ultra wide lens that's cheap and, with a little work and PP, can deliver some decent and unusual images (I'd avoid f/3.5 as much as possible) I think it's worth the very small investment. My rating does take the low cost of this lens into consideration. I'd rate it lower if it cost several hundred dollars.
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I keep some of my favorite pictures here,
The build quality is quite good, metal mount and barrel with a large, smooth operating rubber focus ring. The aperture ring has fixed stops at f/3.5 and f/5.6 then every 1/2 stop to f/22. Another fixed position between f/3.5 and f/5.6 would have been nice however there is room to position the ring between these stops but you don't know exactly what your getting. The hood can be removed but you need it in place to install the cap.
This is a manual focus lens, the depth of field is so deep that even at f/3.5, if you use the distance scale to pick the approximate critical spot you'll be good. The MFD of this lens is 11.8 inches presenting some interesting possibilities. Focusing at the MFD gets a little more difficult if you want the sharpest possible images. Live view X 10 helps for this.
Image quality. Wide open, images are pretty soft in the center and a little softer as you move towards the edges. Sharpness improves a lot at f/5.6. Depending on the lighting, there's a lot of CA at f/3.5, this too improves at f/5.6 but is still visible in the 2 images below.
This one is at f/3.5, nothing is all that sharp and there's heavy CA, especially in the branches in the upper right. (SOOC JPEG)
This one is at f/5.6, the sharpness improves a good bit and the CA is less obvious but still there. (SOOC JPEG)
Just had to do the brick wall, these are at the MFD.
This one @f/3.5, not all that sharp. (SOOC JPEG)
This one at f/5.6, the sharpness improves a lot. (SOOC JPEG)
The color and contrast very closely match the actual scenes.
My conclusion is that if you're a pixel peeping addict who just can't let it go in ultra wide images you may want to pass. If though, you want an ultra wide lens that's cheap and, with a little work and PP, can deliver some decent and unusual images (I'd avoid f/3.5 as much as possible) I think it's worth the very small investment. My rating does take the low cost of this lens into consideration. I'd rate it lower if it cost several hundred dollars.
--
I keep some of my favorite pictures here,
