I have got an old lens Helios 44-2 (58mm f/2 M42 mount) that I want to use for portraits on my Nikon D3100. I used an adapter (without optical element) to mount the lens. I want to really try this before going for more expensive non-cpu prime lenses.

In manual mode I can not select the aperture but only shutter speed and exposure. Moreover there is no option to specify non-cpu lens parameters.

The images turn out to be darker even at f/2 and out of focus.

I have read posts on using live view for focusing and tried that. It improves the focus a bit but not the brightness. Can someone suggest a well documented procedure for improving brightness and focus?


2 Answers 2


In manual mode I can not select the aperture but only shutter speed and exposure.

That's correct. The M42 mount doesn't have any provisions for the lens to interact with the camera in either direction, so shutter speed and sensor sensitivity (ISO) are the only things on the body you'll be able to adjust. Aperture is, obviously, on the lens.

The images turn out to be darker even at f2...

The D3100 is not listed as being able to meter with non-CPU lenses, so anything you're seeing on the meter -- if it's showing you anything at all -- should be taken with a boulder of salt. Correct exposure can be determined using an off-camera light meter or trial and error. Fortunately, trial and error is cheap on a digital body.

If the ISO sensitivity in your camera is set to automatic, it may be defaulting to 100 without proper metering input. It takes a surprising amount light at ISO 100 to get a good exposure, so do some experimentation at 400 or 800 or shoot outside in the sun.

...and out of focus.

Manual focus is difficult on most DSLRs because their focusing screens don't have anything to help you out. Before AF was common, most bodies had a split-prism or microprism focusing aid that made it clear when the image was in focus. There are third-party screens available with one or both built in. They cost just north of $100 but are worth every dime if you're going to do a lot of manual work.


Nikon DSLRs do not play well with M42 lenses, as flange focal distance (46.5 mm) of Nikon F-mount is longer than on the original M42 cameras (45.46 mm). The lens was designed to sit closer to imaging plane (film) than it can physically reach on your DSLR's body, and this robs the possibility of focusing anywhere near infinity; the lens can be focused only in the near range of a few feet. On eBay, you might find adapters with optical element to fix the infinity focus issue, but an optically good one has yet to be found.

No Nikon has been able to set aperture on an M42 lens, ever. So you'll have to do that manually, by turning the narrow ring on the front of Helios 44-2. The camera won't meter with your lens to tell what shutter speed and ISO would suit, but you could determine appropriate exposure settings beforehand with a Nikkor lens attached to camera body instead.

So when you go for more expensive old prime lenses, you'd probably want to stay away from M42 lenses and hunt for second-hand Nikkors (AI, AI-S, AF, AF-I, AF-S) instead - you'll be able to focus with them and your camera would be able to drive the aperture. AI and AI-S would still leave you on your own with metering, and only AF-S/AF-I lenses would auto-focus (unless you upgrade body to a higher level Nikon).

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