Search results for 'sensor cleaning' - page 95
new 18-55
I've been led to believe that the original 18-55 and the K20D would not be a good combination, quality wise... Chris That is what Pentax implied at the introduction of the new models. The original coudn't give enough resolution for the new sensor.
Posted by pentaxian450 on 15/02/2008 - 20:55
new 18-55
I've been led to believe that the original 18-55 and the K20D would not be a good combination, quality wise... Chris That is what Pentax implied at the introduction of the new models. The original coudn't give enough resolution for the new sensor. There's going to be a lot of unhappy Sigma users...
Posted by George Lazarette on 15/02/2008 - 21:00
70mm limited on film cameras?
I know the 70mm 2.4 limited is designed for the digital sensor but so is the 40mm 2.8 limited and that in fact has a big enough image circle for film. So I was wondering whether in fact the 70mm also has a big enough image circle for film. Has anybody tried it - or is there anybody who has one an...
Posted by amilner on 29/01/2008 - 08:05
Lens Options?
Ok thanks, Im looking on the net now and alot are sigma and say for nikon or canon are they not universal? Do they have to say pentax to fit? Yes it must say Pentax Fit. I would suggest a KA type or newer (has an 'A' setting on the aperture ring) as this will maintain all the automatic functions...
Posted by beakynet on 29/01/2008 - 15:23
Filters for the Bigma
Rambling mode on: I guess you could have a point :) Maybe it is a needless worry, because you should expect the newest technology in lens coatings would prevent actual damage from the ''Elements out there''. On the other end i still prefer a good cleaning of a relative cheap filter over a good cl...
Posted by Malo1961 on 08/02/2008 - 21:13
Filters for the Bigma
Rambling mode on: I guess you could have a point :) Maybe it is a needless worry, because you should expect the newest technology in lens coatings would prevent actual damage from the ''Elements out there''. On the other end i still prefer a good cleaning of a relative cheap filter over a good cl...
Posted by Clarky on 08/02/2008 - 21:53
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
Magnification of a lens
Magnification of a lens I'm some what mystified as to how Pentax works out the magnification of its lenses... For the DA* 50-135 zoom the angle of view is quoted as 31.5 to 11.9 degrees, magnification as 0.17x and minimum focus distance as 1.0m (specs from http://www.pentaxslr.com/lenses/lens_...
Posted by Bob and his Pentax on 21/02/2008 - 12:11
Magnification of a lens
Also, the sensor size is slightly smaller than the figures you've used Bob. This would make the magnification come out higher than your results. Dan
Posted by Daniel Bridge on 21/02/2008 - 23:41
Magnification of a lens
Sorry Dan but I disagree with you - Yes I have used the wrong sensor size should be 23.5 x 15.7 (Pentax spec for a K10D) giving a diagonal of 28.26mm But as Mag = image size / object size the smaller image size actualy REDUCES the magnification rather than increases it. Using Tonys modif...
Posted by Bob and his Pentax on 22/02/2008 - 11:38
Magnification of a lens
Not sure what you're getting at Matt - were you being humourous? (I hate emails/forums when you can't get the tone of a post :roll: ). Unless I'm wrong (again), the magnification doesn't change whether you're using 35mm or a APS sized sensor, as the field of view also decreases as the image siz...
Posted by Daniel Bridge on 22/02/2008 - 14:06
Magnification of a lens
Not sure what you're getting at Matt - were you being humourous? Actually, nor was I! :P Of course, magnification does not relate to sensor size - it was just the calculations shown. Just ignore me... it was a bad Friday :) Matt
Posted by MattMatic on 24/02/2008 - 20:26
Devilry with an old Minolta lens…
If a lens can be made to focus its light on the film/sensor plane then it can be used. A lens is a lens. What the result will be will depend on the lens design.
Posted by johnriley on 28/02/2008 - 07:49
Devilry with an old Minolta lens…
The results using the modified Minolta lens in the K10D are confusing. The new minimal focus distance is now 30cm (minimal focusing stop) and the maximum in-focus target distance (at infinite stop) is no more than 1 meter and 10 cm away from the camera. This would imply that the lens is too far away...
Posted by stevo on 28/02/2008 - 17:54
Devilry with an old Minolta lens…
Yes, if the lens-to-flim/sensor plane is different in Pentax and Minolta SLRs there will be a discrepancy. This tends to result in closer focusing and no infinity focus.
Posted by johnriley on 28/02/2008 - 17:57
Devilry with an old Minolta lens…
Thanks John, thanks Stevo, I understand the problematic more clear now. Surely my lens stops a little (perhaps 0.5 mm) far away from the sensor plane when focus to infinite. And this is very well comprehended when I see the logarithmical scale in the focusing lens ring. For the closer distanc...
Posted by dirk1000 on 28/02/2008 - 21:19
Devilry with an old Minolta lens…
Well, the distance needed to move the lens for focus at infinite was not so depreciable. I moved the lens 3 mm back (to the sensor) and I need to do a fine adjust, another 0.5 mm, but for do this I need the help of a lathe to get this little distance! But at least, now I can shot at infinite (wit...
Posted by dirk1000 on 01/03/2008 - 03:12
16-50 Purple Fringing
I'm not sure if it will make you feel any better but mine does it too. However it only seems to happen in extreme conditions and for me ususaly does not detract from the purpose of picture. I'm sure I have seen some comments that suggest that the K10D sensor also contributes to this effect. In a...
Posted by GlynM on 09/03/2008 - 22:17
16-50 problem ?
My 16-50 is a little stiff at the wide end but smooth after about 28mm. I think this is due to the two barrel extension system. The first is stiffer, the second is smoother. As for backfocus, IŁe found this is my K10 being miss calibrated. I fixed it using a hacked firmware and now what I see in foc...
Posted by Tyr on 17/03/2008 - 09:29
16-50 problem ?
My 16-50 is a little stiff at the wide end but smooth after about 28mm. I think this is due to the two barrel extension system. The first is stiffer, the second is smoother. As for backfocus, IŁe found this is my K10 being miss calibrated. I fixed it using a hacked firmware and now what I see in foc...
Posted by Mongoose on 17/03/2008 - 12:39
