Search results for 'back focus' - page 698
Pentax A-50mm / f1:1.4
Taking any picture with depth to it at f1.4 will be disappointing, especially one like this example where you would have to really search for the sharp plane of focus. Try a flat subject and focus very, very carefully....
Posted by johnriley on 13/02/2008 - 23:37
Pentax A-50mm / f1:1.4
In my opinion this lens is indeed cr*p at 1.4. Doesn't bother me since it's so brilliant at smaller apertures - which are still larger than what my zooms can provide. Any idea how it compares with the 1.7 at 1.7 and smaller? If there's not much in it then I'll definitely cross the manual focus 1...
Posted by ChrisA on 14/02/2008 - 07:48
Pentax A-50mm / f1:1.4
Autofocus 50mm 1.7s aren't easy to find or much cheaper than 1.4 versions, so you might as well get an FA 1.4 if you want AF. Manual focus though - perhaps think twice and do further research before opting for a second-hand M or A 1.4 instead of the extremely common, extremely cheap and lighter M o...
Posted by iceblinker on 14/02/2008 - 13:08
Pentax A-50mm / f1:1.4
Thanks for all your input people, I went out today hoping to resolve the issue once and for all. Now I feel worse. :( Matt, I know anyone taking landscape shots at f1.4 needs a slap, but creative opportunities may arise where this may be a possibility. In the original pictures I was trying...
Posted by Galoot on 16/02/2008 - 20:26
Pentax A-50mm / f1:1.4
Surely that shiny spot is too small for the AF to work on? I thought that AF had a rectangle which is used for focus and it looked for what are essentially hard edges in that rectangle. I'd have thought that shiny spot was too small to focus on and the rest of the rocks are lacking much in the way o...
Posted by mikew on 17/02/2008 - 07:58
Pentax A-50mm / f1:1.4
For something 15-20 feet away and of that size focus should just snap in and be spot on. You don't need a tiny spot for that. The first picture is very soft and even at f1.4 and even on a monitor it looks as though it should be much sharper than that. f1.4 should be perfectly useable for images, ...
Posted by johnriley on 17/02/2008 - 09:41
Pentax A-50mm / f1:1.4
It's an 'A' lens not an Auto Focus. I was focusing manually. The little shiny spot was pin sharp in the viewfinder, but when the picture was viewed, it seemed to have focused behind the rocks. The bush behind and to the right in the first picture is sharper than the rocks I had focused on....
Posted by Galoot on 17/02/2008 - 10:00
Pentax A-50mm / f1:1.4
Here's a long shot. Point the camera at a blank piece of sky or similar and then adjust the viewfinder dioptre until the guide lines are as sharp as possible. It doesn't matter where you focus the lens for this, you are focusing your eye on the focusing screen itself. Having set that, go back ...
Posted by johnriley on 17/02/2008 - 10:24
Pentax A-50mm / f1:1.4
I'm sorry I misunderstood about the AF - when using a non AF lens I tend to use the guide from the red AF light and the lozenge at the foot of the viewfinder to reassure myself it's in focus as I don't have the split focussing screen and I always found plain screens difficult to use. I see what y...
Posted by mikew on 17/02/2008 - 10:32
Pentax A-50mm / f1:1.4
The bush behind and to the right in the first picture is sharper than the rocks I had focused on. Which leads me to think there is a problem with the K10D "back focusing". If you think it's back-focusing, stop taking pictures out in the field, and photograph the test chart, , under contro...
Posted by ChrisA on 17/02/2008 - 10:41
Pentax A-50mm / f1:1.4
Thr problem appeared with my DS. Have a go at manual focusing and focus bracketing with your K10D.
Posted by iceblinker on 17/02/2008 - 14:19
Pentax A-50mm / f1:1.4
Galoot, I would have a go in a controlled test situation with the Focus Test Chart. My K10D was back focussing like mad (on all lenses) and it was especially noticeable at very wide apertures. It doesn't back focus any more though ;) I left a thread here about it... (Very interesting that the K...
Posted by MattMatic on 18/02/2008 - 09:54
Pentax A-50mm / f1:1.4
Just tried my K10D and the autofocus back focuses quite significantly on AF - I trid both my F50 1.4 and my Sigma 105 2.8. However manual focus (using my eyes rather then the green hexagon) is fine so it is not the sensor out of allignment (at least not in relation to the focusing screen) but rather...
Posted by amilner on 19/02/2008 - 17:01
Pentax A-50mm / f1:1.4
Wide angle lenses are more difficult to focus accurately anyway, either by eye or by AF systems. However, DOF helps us here, especially when most wide angle shots are at small apertures. All this will be most critical for f1.2 lenses used wide open at short distances....
Posted by johnriley on 19/02/2008 - 17:18
Pentax A-50mm / f1:1.4
Thanks for all your replies. Matt, I think it is 'back-focusing' but not by very much, as it is not noticable when stoped down a bit. I think my messing about with shots at f1.4 has shown it up where it wasn't as obvious before. I do remember your thread on the subject, and will look back ove...
Posted by Galoot on 22/02/2008 - 14:21
Samsung 50-200
I see that someone is selling this lens new at about 100 quid which seems very reasonable http://cgi.ebay.co.uk/Samsung-50-200mm-F4-0-5-6-ED-Pentax-Samsung-New-Stock_W0QQitemZ350024520628QQihZ022QQcategoryZ30070QQssPageNameZWDVWQQrdZ1QQcmdZViewItem Some years back I bought a refurb camera off ...
Posted by mikew on 14/02/2008 - 08:01
Samsung 50-200
I got mine a while back here: http://www.pcwb.com/catalogue/item/SAMDCA02
Posted by wasleys on 14/02/2008 - 17:57
FA 35's likely to be sold for new DA35 Macros?
The FA is faster (f2.0) and slightly smaller and lighter (as it does not have to focus so far) then the DA Ltd. It also works with film cameras. Those of us that have one as a 'standard' lens (on digital)are not so likely to part with it. OTOH when the DA*30mm SDM emerges you may see some 35 FAs on ...
Posted by amilner on 17/02/2008 - 11:02
Mystery Lens??
It looks like an earlyish Sigma lens to me due to the style of typeface used for the barrel markings. I doubt it's a macro lens as it seems to only focus down to 0.3m - unless the distance scale extends further than we can see. The 'lock'/'unlock' ring makes the bottom of the lens look like an uncom...
Posted by spbatt on 17/02/2008 - 14:10
Mystery Lens??
It looks like an earlyish Sigma lens to me due to the style of typeface used for the barrel markings. I doubt it's a macro lens as it seems to only focus down to 0.3m - unless the distance scale extends further than we can see. The 'lock'/'unlock' ring makes the bottom of the lens look like an uncom...
Posted by Clarky on 17/02/2008 - 20:21
