Focus problem with new 50/2 cron

[danlindberg]

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I have a brandnew 50 cron and I wasn't impressed with the first landscape shots I made. I set up the camera on a tripod and made a careful focus test and, in fact, when focus confirmation in the viewfinder is spot on, then the image is sharp at a closer distance.

 

I am obviously going back to the shop where bought, but I would like to ask if this is common with this lens? and should I ask for another lens or is it common praxis to send it to Solms?

 

I can add that the only other lens I have (while waiting for the 75 cron) is a 24 Elmar which is absolutely amazing in the sharpness department!

 

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[Guest mc_k]

Could be the lens, camera, or both. A lens like a 24 is not ideal to double-check the camera. Maybe the shop will let you try some other lenses.

[archi4]

Try another lens 50mm or longer with f 1.4 or 2.0.

Another thing you can check is if your camera rangefinder is properly set at infinity.

For that you can use your 24 or maybe the summicron. Check if when you focus the lens all the way to infinity while looking at a very far away object (moon, star or very far away church tower) the rangefinder images cover each other perfectly. if the movig image in the rangefinder patch goes past the fixed image then your camera is front focusinng.

 

regards maurice

[danlindberg]

Thanks for reply!

I did a test at infinity too. The alignment is perfect in camera at infinity. When turning it out of alignment the image gets sharper......

 

[archi4]

This isn't far enough away!

A very far church tower is what I meant.

At least 2 kl away

[danlindberg]

Infinity is infinity. On my camera there is no difference in focusing at 40 metres or 800 metres. I am courious how this matters? But I'll try a churchtower far away even if it will be a very very little part in the image with a 50....

[tobey bilek]

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You are not far enough away. I use a star on a clear night as it is easy to see if merged.

 

To stay on earth, use a target a mile away.

 

If you pass that test, the other set point is one meter from the film plane. All 50`s have a 1 meter calibration point.

 

So now you have your meter stick out, put it at 45 deg to the lens axis and do a shot of 18" mark. When processed, 18" should be the sharp point, not 17.5 or 19.

 

A newspaper at 45 deg can work fairly well also. Or a fence. Mark the focus area with tape.

 

Look up converion tables. A meter is close to 39.5 inches. Film plane is the circle with line thru it, at least with a film M. No clue on digital. Estimate i guess. Sensor is 28.5 mm from the lens mount flance, so buy a ruler.

 

Home Depot sells a nice aluminum yard stick for $3. It will serve you for life if you hang it properly.

[ockie50]

Hej Dan,

interesting to hear about your focus problem. I have the same with my brand new Summicron 50/2 bought just 2 weeks ago from Cyberphoto. If I take a photo of a brick wall, the bricks on the wall are sharper on both the left and right edges than at the centre of the image. At 100% the centre sharpness it too poor in my opinion for this lens. Something must be wrong...

[ramosa]

I had this lens for almost three years--and did not experience a problem like this. Indeed, send it back to the seller.

[Leicakillen]

Hej Dan,

We have seen many post re focus problem. I also had this problem and sent camera + lenses to Germany for adjustments, I think it is important to send both. I handled this via my dealer in Stockholm (Wibergs, very helpfull) but was also in contact with the Nordic representative in Copenhagen. In fact my camera was in Solms two times, the Germans did a bad work the first trip. For newer lenses and M9 this did not cost me anything, but took annoying time.

 

Lycka till,

/Anders