Snakepottery Posted March 22, 2010 Share #1 Posted March 22, 2010 Advertisement (gone after registration) Hi all, What's the best way to check for back focus on my new CV 50mm f1.5? I have taken a couple of test shots of the corner of a book at full aperture. It seems as if the focus is a few inches behind the corner rather than bang on. Are these lenses prone to this and is it something I should send it back for? Cheers Andy Link to post Share on other sites More sharing options...
Advertisement Posted March 22, 2010 Posted March 22, 2010 Hi Snakepottery, Take a look here CV 50mm f1.5 back focus. I'm sure you'll find what you were looking for!
DOUG66 Posted March 22, 2010 Share #2 Posted March 22, 2010 Hi, E-mail me your postal address to reidcrabtree@eircom.net and I will post you a copy of the chart that I use to test back/front focus. The chart looses definition if it is attached to an email. Doug. Link to post Share on other sites More sharing options...
Islandmike Posted March 22, 2010 Share #3 Posted March 22, 2010 Hi Andy If you go to this site, there is a chart some way down the page you can print/download. Shoot some shots at around 45 degrees focusing carefully on the central bar, then compare the results with the info on the page where the chart is. You don't have to be hugely scientific. My CV 50/1.5, which I bought nearly new condition off ebay is spot on, so cannot say it is an issue with the product. The other test that I do for spot on focus is to shoot any internet chart, such as a weather forecast by moving the camera back and forth until the rangefinder shows it's correct, then pressing the button. The LCD screen lines are so fine that you can see if they are crisp and clean on the image. Hope that helps Cheers Mike (ex-Gloucestershire may years ago) Link to post Share on other sites More sharing options...
vafa Posted March 23, 2010 Share #4 Posted March 23, 2010 I set a regular ruler on it's edge on a table at 45 degree to the camera and took shots at different f stops, aiming at a number in the middle.(I had focus shift on my Cv35 1.4. It was back focusing starting at f2.8 to f4.) You can then see where your lens is at it's sharpest. Vafa Link to post Share on other sites More sharing options...
Snakepottery Posted March 24, 2010 Author Share #5 Posted March 24, 2010 Thanks Gents, useful info there. I'm going to have a proper play at the weekend in decent light and see what's what. If it shows an issues, I presume I can return it for repair as its new? Andy Link to post Share on other sites More sharing options...
ottocrat Posted March 24, 2010 Share #6 Posted March 24, 2010 You should certainly be able to get it repaired under warranty; if your dealer is one of the good guys, he may even swap it for another new 50/1.5 (which may or may not suffer from the same back focus problem, hopefully not). Link to post Share on other sites More sharing options...
Snakepottery Posted March 24, 2010 Author Share #7 Posted March 24, 2010 Advertisement (gone after registration) Got it from Robert White in Poole so, yes, one of the good ones! But will make sure there is a problem before going down that road! Andy Link to post Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.