Search results for 'back focus' - page 779
F.O.A. Scottthehat; Focus tests as requested.
You should try Yvon Bourque's newer focus chart. There is too much "crap" on this one to accurately figure out where the camera has locked focus. Here is where you can find it:
Posted by pentaxian450 on 23/05/2009 - 01:53
F.O.A. Scottthehat; Focus tests as requested.
The last shots look "woeful" because it appears you have a quite bad front focussing issue. You will not see this in an image of a flat subject that is parallel with the sensor's focal plane. It's obvious in the shots of the chart though. Yes, any adjustment for focus issues at one end of the zoo...
Posted by Mannesty on 23/05/2009 - 06:08
F.O.A. Scottthehat; Focus tests as requested.
Many modern zooms are not zooms at all but varifocals. They do not hold their focus when zoomed. Very expensive ones do, very cheap ones definitely don't, but there's a whole grey area between those two extremes where some hold focus better than others. Try it. Manually focus very precisely on so...
Posted by johnriley on 23/05/2009 - 06:13
F.O.A. Scottthehat; Focus tests as requested.
That's true John but I've assumed Craig has refocussed at the different lengths of zoom for his tests.
Posted by Mannesty on 23/05/2009 - 06:41
F.O.A. Scottthehat; Focus tests as requested.
The last shots look "woeful" because it appears you have a quite bad front focussing issue. You will not see this in an image of a flat subject that is parallel with the sensor's focal plane. It's obvious in the shots of the chart though. Yes, any adjustment for focus issues at one end of the zoo...
Posted by CraigF1969 on 23/05/2009 - 09:02
F.O.A. Scottthehat; Focus tests as requested.
Many modern zooms are not zooms at all but varifocals. They do not hold their focus when zoomed. Very expensive ones do, very cheap ones definitely don't, but there's a whole grey area between those two extremes where some hold focus better than others. Try it. Manually focus very precisely on so...
Posted by CraigF1969 on 23/05/2009 - 09:04
F.O.A. Scottthehat; Focus tests as requested.
You should try Yvon Bourque's newer focus chart. There is too much "crap" on this one to accurately figure out where the camera has locked focus. Here is where you can find it: hi craig try this focus chart, if its has major front focus as it looks like it has in the first chart pics the k20 wi...
Posted by scottthehat on 23/05/2009 - 09:49
F.O.A. Scottthehat; Focus tests as requested.
Hi Craig, I don't know if you have software for comparing shots or not. The FREE Farstone Viewer lets you compare two at a time and will also smooth the screen when you zoom to say 200%. I can't see a way of capturing the screen other than pressing "Print Screen" and then pasting into MS Paint ...
Posted by shim on 23/05/2009 - 09:53
F.O.A. Scottthehat; Focus tests as requested.
I realise its not a very expensive zoom John but i would still have expected a lot better from a £600 lens. I would say it was an expensive Zoom :lol: shim
Posted by shim on 23/05/2009 - 09:55
F.O.A. Scottthehat; Focus tests as requested.
I realise its not a very expensive zoom John but i would still have expected a lot better from a £600 lens. I would say it was an expensive Zoom :lol: shim Its very expensive to me also but i am not going to compare it to a 3 grand lens for comparison. I will try some more tests as its very ov...
Posted by CraigF1969 on 23/05/2009 - 13:13
F.O.A. Scottthehat; Focus tests as requested.
Craig, your only testing and interested at the 400mm end, so disregard all the other stuff. Personally I think the front focus problem might be what's causing the slow focus, so I would adjust the camera and try to eliminate the error at 400mm f/5.6 ONLY the other apertures should fall into plac...
Posted by shim on 23/05/2009 - 13:34
F.O.A. Scottthehat; Focus tests as requested.
About to post some more tests with 3 different lenses and some really eye opening results.
Posted by CraigF1969 on 23/05/2009 - 14:30
F.O.A. Scottthehat; Focus tests as requested.
I realise its not a very expensive zoom John but i would still have expected a lot better from a £600 lens. £600 is an expensive zoom in my book!
Posted by johnriley on 23/05/2009 - 19:24
Extensive focus Tests with 3 different Lenses.
Conducted some more focus tests although a little more extensive than before using 3 different Lenses. First 3 are all the 120-400mm @ various ranges and at f5.6. Focus Point on the First 3 was the Word Ingredients. 120mm 148mm 300mm 400mm We will now move on to Focus Ch...
Posted by CraigF1969 on 23/05/2009 - 14:43
Extensive focus Tests with 3 different Lenses.
Your too far away from the test chary with the 50mm Craig. If you get say .45m away it will be more obvious like this: I can't see which way the adjustment is getting better, you need to be at 45deg to the chart and it looks like +-10 isn't enough. Will the K20D go to +-20? The box shots ...
Posted by shim on 23/05/2009 - 15:02
Extensive focus Tests with 3 different Lenses.
Craig to me the 16-45 @f4 chart is the-10 I would set at _8. At 400 f5.6 -10 not enough, I would settle for the 16-45 at around -8ish but would send the 400mm lens back, but in saying that the 50mm f1.4 is not good, so I would still suspect your camera has a fault as well.:?
Posted by ttk on 23/05/2009 - 15:06
Extensive focus Tests with 3 different Lenses.
The 50mm at plus 10 is OK.... so it's not the camera. The other two 50mm shots are just not in focus or have camera shake. You need to get the 400mm sorted out and then take a shot of the box filling the frame at f/5.6 and then another with the 50mm filling the frame (with +10) setting and at f/5...
Posted by shim on 23/05/2009 - 15:14
Extensive focus Tests with 3 different Lenses.
The 50mm at plus 10 is OK.... so it's not the camera. The other two 50mm shots are just not in focus or have camera shake. You need to get the 400mm sorted out and then take a shot of the box filling the frame at f/5.6 and then another with the 50mm filling the frame (with +10) setting and at f/5...
Posted by CraigF1969 on 23/05/2009 - 15:26
Extensive focus Tests with 3 different Lenses.
Craig, Please forgive me for asking a what may be stupid question. Are you tilting the focus adjustment chart at 45 degrees to the axis of the lens (i.e. is the back focus end of the chart farther away than the front focus end)? I ask this because in the focus chart pictures the front and b...
Posted by Bob and his Pentax on 23/05/2009 - 17:19
Extensive focus Tests with 3 different Lenses.
Craig, Forget that chart, it's much too busy/fussy/noisy at the most critical focus point. Use instead. Each of them has exactly one high contrast boundary for focussing, unlike your charts. Chose the one appropriate to the lens you are testing. For best results they should be printed on ...
Posted by Mannesty on 23/05/2009 - 17:42
