Search results for 'back focus' - page 1590
K-5 - How accurate can I expect the focussing to be?
Thanks for the reply! The shots above were in bright window light. I've now calibrated three lenses by first using Live View with full magnification and manual focus, then marking the focus ring, and then making menu adjustments until the AF turned the ring to the exact same mark (all on a sturd...
Posted by karma mechanic on 26/02/2011 - 14:15
K-5 - How accurate can I expect the focussing to be?
Picture 1 - manual focussing using the AF beep to indicate correct focus Your first misconception (you are not alone). The beep and red square in the viewfinder do not indicate correct focus. They indicate only that a focus point has been selected. The one and only electronic indication that a...
Posted by Mannesty on 26/02/2011 - 14:47
K-5 - How accurate can I expect the focussing to be?
[quote:3496ace15f="karma mechanic"] The beep and red square in the viewfinder do not indicate correct focus. They indicate only that a focus point has been selected. The one and only electronic indication that a lens is correctly focussed on the selected focus point is the green hexagon in the b...
Posted by karma mechanic on 26/02/2011 - 15:02
K-5 - How accurate can I expect the focussing to be?
It is the manual focussing that I want to improve since the clearly-defined focus zone on the ground-glass isn't precisely where the actual sensor image is sharp. That is something findamentally out of adjustment. If the distance from lens to ground glass and from lens to sensor is not the same then...
Posted by johnriley on 26/02/2011 - 16:18
K-5 - How accurate can I expect the focussing to be?
This is a shot of a Tesco leaflet, at an angle, with the 55mm 1.7, focussed using live view on the '13': (100% crops) This is what I get if I use the ground glass very carefully, focussing on the '13': With an adjustment of -10 the focus confirmation hexagon lights and gives a result...
Posted by karma mechanic on 26/02/2011 - 17:07
K-5 - How accurate can I expect the focussing to be?
What lens is this? I'm not familiar with any Pentax 55mm f1.7. It is a Minolta Rokkor 55/1.7, purely manual focus of course. I've been using it to get a feel for using a fast prime with very small DOF and manual focus, then when I've sold the Rokkor 85/1.7 as well I plan to get the Samyang 85/1.7 f...
Posted by karma mechanic on 26/02/2011 - 17:32
K-5 - How accurate can I expect the focussing to be?
Should not make any difference in manual focus though... if what you see isn't what you get when relying on the focussing screen, something isn't right. Does the dioptre need adjusting perhaps? [edit - just spotted you already did that]... But given that these are 100% crops, aren't they within t...
Posted by Pentaxophile on 26/02/2011 - 20:22
K-5 - How accurate can I expect the focussing to be?
Regarding the margin of error, taking the lines of text as an example it is easy to focus on a single line on the ground glass. Getting a different line in the final image is a bit disconcerting :) The lens to ground glass distance does need to be exactly the same as the lens to sensor distance ...
Posted by karma mechanic on 26/02/2011 - 20:56
K-5 - How accurate can I expect the focussing to be?
3] Focus screens can't display a DOF thinner than that from around F2.8. i.e take a picture at 1.7 and the front and back of the scene will be more OOF then what the focus screen shows. Don't know if you missed this or not ^^^ but when manual focussing with wide apertures you can think te im...
Posted by Smeggypants on 26/02/2011 - 21:11
K-5 - How accurate can I expect the focussing to be?
Well I've successfully AF calibrated my Sigma 30/1.4 and FA50/1.4 and the results are accurate and consistent ( K-5 front focus fault notwithstanding of course ) Live-view uses contrast at a specified location no needs no adjustment, it is just slower. Indeed. very slow but great for staged sho...
Posted by Smeggypants on 27/02/2011 - 00:22
K-5 - How accurate can I expect the focussing to be?
Yesterday I ordered a K-5. It arrived today, so after charging the battery I tried a few things just to get a feel for the camera. Mostly they've filled me with confidence, or even exhilaration, compared to the GX10. However, one gripe with the GX10 was that the focus screen was never quite in ...
Posted by awaldram on 04/03/2011 - 11:45
K-5 - How accurate can I expect the focussing to be?
Fast lenses always give an focus error, read the part about focus shift. http://toothwalker.org/optics/spherical.html Not only fast lenses though but the effect is most pronounce with those. When you look at the amount of aberration you have with that lens it's no wonder the AF is off.
Posted by Anvh on 04/03/2011 - 14:52
K-5 - How accurate can I expect the focussing to be?
Using AF.C and tracking the red square over objects it appears that the area covered by the AF sensor is much bigger than the red square, so that's one misapprehension cleared up. It appears to be a little smaller than the area inside the central curved marks on the screen. Regarding focus shift,...
Posted by karma mechanic on 04/03/2011 - 15:14
K-5 - How accurate can I expect the focussing to be?
Regarding focus shift, the picture of the camera dial and the later ones of the text were taken wide open, so no shift on stopping down. Sorry might not have been fully clear it's spherical aberration that can cause it Here is a lens. Wide open the best point of focus is at point B since the ...
Posted by Anvh on 04/03/2011 - 16:44
K-5 - How accurate can I expect the focussing to be?
Yup contrast focus is more accurate but it's also a lot slower. Faults like the current low light front focus on the K-5 aside I've always found phase AF to be good enough though. In real critical situations I've always gone into live view and manually focussed. Although that relies upon exactly sa...
Posted by Smeggypants on 04/03/2011 - 20:48
K-5 - How accurate can I expect the focussing to be?
Actually I made a silly mistake, live view doesn't rely upon "exactly same optical distance between subject and sensor and subject and focussing screen" Dunno why I said that. My point about Live view, which I should have mentioned as it's the important point .... is that you can magnify it....
Posted by Smeggypants on 04/03/2011 - 21:19
K-5 - How accurate can I expect the focussing to be?
Cameron deliberately used a soft focus technique for her portraits, including being OOF. My understanding is that she was criticised even in her own time for this, and that it took some time for appreciation to grow. I would not call this poor technique since the methods and result were exactly her ...
Posted by rparmar on 05/03/2011 - 17:47
K-5 - hand-held IR pictures at last?
The answer is maybe. One of the things I hadn't seen fully resolved was the issue of the IR sensitivity, so this afternoon I tested it in between rain showers. I've got a Samsung GX-1L (= Pentax *ist DL2) that can do handheld IR work in good light at high ISO, but you can't see through the viewf...
Posted by karma mechanic on 26/02/2011 - 14:55
GGS Screen Protector For A Samsung GX10
I had similar problems with my GX20 and put a K20D one on. Although the viewable areas are the same between the K20 and GX20, the actual shape of the back plastic/screen are slightly different. The GX20 being slightly more curved on the left and right hand edges and possibly taller although I ...
Posted by carmagw on 26/02/2011 - 20:02
PK_Tether v 0.4.5 released
As an amateur astrophotographer and a Pentax K7 owner I have been looking for software that will allow me to use the mirror-up facility in the K7 remotely for critical astro photos. TK_Tether does not yet implement this function, however I have discovered that TK_Tether can be used in conjunction wi...
Posted by gbansel on 29/12/2011 - 19:45
