Lens Comparison

[John Parry]

Haven't a clue where to put this, but....

I got the test roll back from my new Mamiya MSX500. I like it very much (a little short of shutter speed but that doesn't matter too much). My new avatar shows me holding it - it's a reflection from a smoked glass window.

I plunged for the MSX because it's M42, and I didn't want to get into yet another lens standard. So I tried a comparison between a few of my M42 lenses. The problem with this is that modern processing tends to iron out subtle differences (on negative colour film anyway).

But one of the things I'm interested in is close focus performance. I've banged on a few times about how good the Carl Zeiss Jena Tessars are in this respect. So I made up a little test sheet, using a scale of measurement that we've all become familiar with - font sizes. If anybody wants to replicate the experiment (which I have to say wasn't scientifically conducted at all) the font used is Arial. Here are pictures taken at the closest point of focus (as best I could get it with my eyesight), with four M42 lenses. See for yourselves:

Mamiya/Sekor 50/2



Asahi/Takumar 55/1.8



Carl Zeiss Jena Tessar 50/2.8



Praktica Pentacon 50/1.8



Seen like this, the differences are far more descriptive than a lens test report. Of course, at the end of the day, you can make any lens do what you want it to using extension tubes, reversing rings or bellows, but I thought it was interesting.

Regards - John

[Journalist]

Interesting. I prefer these tests instead of funny numbers and fancy curves. this is the only test one ever need. Real life performance done by a photographer and not a lab. Thanks John for a very useful input.

[Dan Vincent]

John,

One test I've used a few times is to tape a newspaper page to the wall.

This will show up any "barreling" or loss of sharpness at the edges.

Most lenses have a "Sweet-Spot" at around f5.6 or f8 that delivers excellent images. Shoot all the different stops and see how much it might vary.

Use a grey card to make sure you don't underexpose.

Most guys here probably already know this but just in case there is someone new who is looking for a way to check a lens.

[John Parry]

Hi Dan,

Wasn't bothered about the exposure, it was just the focussing distance I was interested in.

Yes, these little tests aren't precise or scientific, but they tell us what we need to know. Don't worry whether people have heard a tip like this before. We are all here to learn (among other things), and for everyone who thinks 'Ho-hum' there is liable to be someone else who is thinking 'Mmm - never thought of that, must give it a try'

Regards - John

[Microdad]

Thats a great test John... It looks like the Carl Zeiss comes out on top.

Steve