Recently, I got some old m42 prime lens from Ebay and started playing with them with my Canon T3i/600d. However, it's difficult to get sharp pictures with these manual focus lens as there is no AF (electronics and motor etc) and adapter was no help either. On some forum, someone told about the metering mode could affect the picture with these lens (but didn't clarify how).

My question is, what is the best metering mode for these m42 manual prime lens? and, how does different metering modes can affect the performance of these manual lens?

I tried evaluative and weighted center average, but couldn't spot a difference.

  • I have the same situation as you: A 550D with a m42 50mm/f1.8 prime lens. I too struggle to get sharp pictures without the AF. I use the Liveview focussing to get the a sharp picture as focussing through the viewfinder does not give satisfactory results. The metering mode is not going to help with the sharpness. Jul 20 '12 at 0:49
  • What I do notice is that after attaching the lens I have to dial in a certain exposure compensation (-2/3 ev) such that correctly exposed photos come out. I use this exposure compensation value as a baseline value and under/over expose w.r.t. that value. Here is a link explaining metering modes: photo.stackexchange.com/questions/4687/… Jul 20 '12 at 0:50
  • @BartArondson: Recently, I got the AF chip adapter (previous adapter was without any AF confirmation chip) and now it seems to work. Also, I did experiments with different exposures and I must say that under or overexposure didn't work for me. Instead, I got better results by changing the shutter speed (by going to manual mode) and now, I have chip adapter, the exposure is automatically adjusted by the camera when the focus is locked so everything seems to be fixed now. Jul 28 '12 at 1:47

I have an Auto-Chinon 135mm f/2.8, in M42 mount that I bought off eBay for a princely sum of about £20. As a previous poster says, it takes practice practice practice. I ended up mostly using (M)anual mode on the camera, as although it was an f/2.8 lens, the display on my 7D only ever told me it was an f/1.4!

The metering itself came almost naturally after a while. I guess older photographers who remember the old manual cameras will get on easier than us young'uns, but on a bright day, I'd set ISO 100 or 200, and then go from there. If I was wide open at f/2.8 I'd start with a shutter speed of about 1/320th, take a picture, and check the display. Adjust as necessary. If I wanted to stop down to f/8, I might boost the ISO to 400 and drop shutter speed down to 1/125th? There is no specific guidance as such but I just used a try, view, adjust, repeat methodology. Maybe this isn't the best way to do it but it's an option.

Don't forget if you shoot to RAW, its easier in post processing to make exposure adjustments as necessary so you can reduce or increase the brightness (to a certain extent) later.

As for focussing, the M42-EF mount adapter I had, albeit a cheapo one from Hong Kong (also from eBay) had some little electronic contacts on it that seemed to make the focus confirmation light work. I imagine your 600D would have the same thing? If you look in the viewfinder, at the bottom-right, when you are focussed on a subject, a green dot appears - I used this to know if I was in focus or not.

  • I got a normal adapter without chip but later realised that AF chip can help. I've already ordered it now, hope it'll improve the sharpness. As far as metering mode goes, I watched a video over youtube where someone did a comparison and found that center metering work best if you've uneven exposure (sunlight from a window). Over exposure is a problem with m42 lens at wide open and my guess is, if we'll use the center metering with these lens maybe we can improve sharpness in certain situations (indoor, macro etc). I did a check again and I can see subtle edge over evaluative metering. Jul 20 '12 at 13:04
  • I found that there are two kind of chip adapters available over Ebay (doing some research before odering), AF chip (cheap) and EMF AF chip (little expensive but programmable). If you have EMF AF chip, maybe you can program it for your lens aperture setting. Then, it'll sent the correct EXIF data to the file. Maybe, it will also help in metering mode and sharpness, who knows. Will check mine when it'll arrive. Jul 20 '12 at 13:14

I'm afraid changing the metering mode won't affect your ability to focus properly. If your lens doesn't have any kind of reporting of an achieved focus, you have basically 2 options

1.) focus using your viewfinder, and practice, practice, practice. Over time you'll get better.

2.) focus using your LiveView. This way you can zoom in, check the focus etc.

However, I believe the second approach is good only if your subject stands still and you have a tripod. At least for me it's easier to use a viewfinder if my subject moves, because that way I have more stability and freedom comparing to holding my camera in front of me, trying to see something on that LCD... Not mentioning the struggle when you try to focus using LCD during a bright sunny day.

  • @Bart & Walther: I agree about using the live view instead of viewfinder. Moreover, I want to add two points: 1. It seems that these m42 lens sharpness also depends on the aperture. Some lens from my collection like Pentacon 1.8, 50 mm is soft at wide open but another one, Pentacon 2.8, 135 mm is sharp even at wide open. So, Maybe higher aperture number help a bit but you'll lose some light, prospective and Bokeh! 2. Some guys (like Mike) have confirmed using AF/EMF AF chip lens adapter which can help to focus correctly. Jul 20 '12 at 12:48

I got the best results with m42 lenses while using Magic lantern !!! Of course, you should have a ML compatible Canon EOS, M42 lens, and a chip-adapter İnstall and make ML active Make "Trap focus" function active. Select the the focus points as you usually do, or use the "pattern" function of ML While shutter half pressed. Slowly adjust the M42 lens. Canon will automatically shoot immediately when the focus is obtained. This is supposed to be the "sharpest" point for the lens. This is my solution. Pars


I'm a vintage lens fan and use them on my 40D. Metering has no impact on your focus. I have M42 Carl Zeiss Jena 135mm 3.5 and Pentax M 50 1.4 - both adapters have the AF chip. The M42 chip is dead-on but the one on my pentax k adapter is a bit off. The exif data is hardcoded to 50 1.4 on both. Now you can get the chips called "EMF" that you can program to the lens you have the adapter on. That's pretty cool.

The good thing about the AF even when it is a bit off is that it gets you close, and then you can learn which direction and how far to "flick it". I have to do this with one of my canon lenses as well.

However, there is a trick to getting better at manual focus you can practice (just do sessions every day with manual focus fast switching from near to far and people moving around you). if you focus from infinity to "meet your target" and you pass the point where it goes from blur to perceived sharpness in the viewfinder and then get to the point where it gets blurry again - then you just need to go a notch back (towards infinity) - about 1/3 (not 1/2) of the distance back to the first blur-focus point.

This may be slightly easier for me with a pentaprism viewfinder, but maybe the technique can help you, too.

Random shot from my practice session today with Carl Zeiss Jena 135mm 3.5:

Carl Zeiss Jena 135mm 3.5

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