Help with Rokinon 8mm F3.5 Fisheye

Hey folks,

Just picked up a used Rokinon 8mm F3.5-22 fisheye lens. I know it is all manual and have the process of obtaining fairly good exposures without too much problem.

Where I am having problems is trying to nail the focus. So far, I have been able to get 1-2 half decently sharp images. The others seem to be out of focus in pretty much the whole image. I am using a shutter speed of between 1/125 and 1/500, so I don't think motion blur would be an issue.

The image of the bush is one that seems relatively sharp and the image of the backyard is out of focus all over.

Backyard:
ISO 100
F/5.6
Shutter 1/60

Bush:
ISO 100
F/5.6
Shutter 1/60

Any help or ideas would be greatly appreciated.

Could there be something wrong with your lens? I suggest re-taking both test shots using various settings on the focus scale. See what happens. Is the focussing scale accurate?

I recently bought the same lens and am quite satisfied with it. But I have had several problems. First, I find it impossible to focus through the viewfinder of my 70D, even when I use live view and 10x magnification. This might be because the lens is soft at f3.5 and the depth of field is so great that everything is in focus anyway. I normally use it at f/5.6 indoors and f/11 outdoors. I focus manually using the distance scale.

Second, when using the Av exposure mode, I get good exposures indoors, but grossly overexposed shots outside. Outside, I resort to the manual mode and the "sunny f/16" rule, i.e. ISO 100, 1/200@f/11, etc.

In the POTN forums is one for lens sample images. Find the Rokinon fisheye thread for samples and other comments about the lens.

Use 10x magnification in LV to see if you can get anything in focus, it's not uncommon for these lenses to have their focus rings miss-aligned and it's easy to fix if that is the problem. Generally if you just focus to infinity most things will be in focus even when wide open.

Thanks for the info guys. I have tried going all the way to F22, but was mainly at F5.6. I tried focusing from 1 foot all the way to infinity. The backyard image was set with focus almost to infinity. I only paid $149 USD for the lens, so perhaps it is a bum lens?

Chopper Al wrote in post #16937195
Thanks for the info guys. I have tried going all the way to F22, but was mainly at F5.6. I tried focusing from 1 foot all the way to infinity. The backyard image was set with focus almost to infinity. I only paid $149 USD for the lens, so perhaps it is a bum lens?

Again, check the focus in LV. They're often off from the factory, all you have to do to adjust it is pull back the rubber on the focus ring and loosen a few screws, adjust the ring, tighten it back up and you're good to go.

EverydayGetaway wrote in post #16937283
Again, check the focus in LV. They're often off from the factory, all you have to do to adjust it is pull back the rubber on the focus ring and loosen a few screws, adjust the ring, tighten it back up and you're good to go.

Once you calibrate your distance ring. Keep it at 10ft and set at f8. Everything should be in focus with those settings.

Hi there, I have the Samyang 8mm (same lens) and I never focus the lens. All I do is set the focus to just under infinity and bobs your uncle, sharp every time. Hope this helps.