Search results for 'sensor cleaning' - page 101
SMC Takumar 135mm problem
If it's oil (it usually is) then there's nothing you can do about it beyond send it off for cleaning. Depending on what you value the lens at, it'll be worth it or not. Certainly given the financial value of the lens, then it's bin fodder. Personally I'd get it cleaned as it sounds like you've got a...
Posted by GrahamNR17 on 14/01/2009 - 17:08
SMC Takumar 135mm problem
Kris, Just curious, I have two M42 135mm primes - both Super Takumar's. One I use for Macro work, the 1:3.5, the other for portarait work, the 1:2.5. They are both wonderful, but I LOVE the 2.5. They are constructed very differently. This is most obvious when you watch the rear elements whi...
Posted by Mac on 15/01/2009 - 13:54
SMC Takumar 135mm problem
Hi Kris. I know nothing about cleaning the inside of lenses but in my days in engineering I had to teach people to clean Air Bearings and the recommended fluid was ACETONE. This leaves absolutely no residue and evaporates almost instantly. (DO NOT USE LADIES NAIL VARNISH REMOVER AS THIS HAS AN ADDIT...
Posted by vic cross on 16/01/2009 - 13:20
Pentax postponed the launch of DA Star 55mm F1.4 SDM to February
but its impact on perspective will still be a 55mm lens, not an 85mm lens, won't it? Thats a very interesting point Kris, certainly one my brain would never have thought of:oops: a 55mm lens will form exactly the same image on an APS sized sensor as it would on 35mm film, you just dont get all the i...
Posted by fatspider on 25/01/2009 - 00:50
Pentax postponed the launch of DA Star 55mm F1.4 SDM to February
Thats a very interesting point Kris, certainly one my brain would never have thought of a 55mm lens will form exactly the same image on an APS sized sensor as it would on 35mm film, you just dont get all the image on the sensor. BUT...would a 55mm lens designed to form a smaller image circle have...
Posted by johnriley on 25/01/2009 - 01:17
Pentax postponed the launch of DA Star 55mm F1.4 SDM to February
Just make a topic out of the matter of comparing the FA* 85mm f/1.4 and the DA* 55mm f/1.4 on differend sensorsizes in the general chat. There is a difference in depth of field because of these points; - If the sensor is smaller you lens need to have sharper to capture the same amount of detial as...
Posted by Anvh on 25/01/2009 - 04:13
Pentax postponed the launch of DA Star 55mm F1.4 SDM to February
What you need in smaller formats is not more sharpness but more resolution. Also a higher degree of manufacturing accuracy. You also define a smaller circle of confusion, which takes care of your increased magnification requirement. In the case of digital there will be no loss in theoretical ...
Posted by johnriley on 25/01/2009 - 09:25
is this lens on ebay worth a punt? SMC Pentax-FA 1:4.7-5.8 100-300mm
"These are sold for spares or repair - they've got some some mould inside (from storage in high humidity), but my research tells me that this can be relatively easily solved - you just need to open them and clean them." Just? :shock: Cleaning a fixed focal length, manual focus lens is one thin...
Posted by Daniel Bridge on 27/01/2009 - 15:39
Macro Magnification
No, a 1:2 500mm is not the same as a 1:1 1000mm. The size ratio is the physical size of the image on the film frame (or sensor) in relation to actual size of the object. So a 1:1 macro gives the same sized image on the film as the object measures in real life. A 1:1 macro gives you a life sized i...
Posted by MarkD on 06/02/2009 - 21:05
Macro Magnification
So what are the differences between a 28mm, 50mm and 100mm macro lens? I am sure it can't be so but wouldn't the best be the longest? A 28mm, 50mm or 100mm macro lens is the same as any other 28mm, 50mm or 100mm lens except that they allow much closer focusing allowing --- if they are "true" macro l...
Posted by womble on 09/02/2009 - 20:49
Mk II Kit Lens
I've been quite happy with my Mark I lens (the foggy trees photos were taken with it for example). So much so that when faced with the choice of replacing it with a DA 16-45mm or DA* 16-50mm, or buying something utterly different and keep using the kit lens, I went for the utterly different. The f...
Posted by womble on 08/02/2009 - 19:19
Prime lens focussing problems
How far out would you guess it to be? Measuring from the front of the lens would make that measurement out to the tune of the lens length plus flange-to-sensor distance. Unless things have changed, the scale on the lens is the subject-to-film distance?
Posted by GrahamNR17 on 08/02/2009 - 20:56
Prime lens focussing problems
How far out would you guess it to be? Measuring from the front of the lens would make that measurement out to the tune of the lens length plus flange-to-sensor distance. Unless things have changed, the scale on the lens is the subject-to-film distance? Hi, this may be true, but given that the tests ...
Posted by Miniman on 09/02/2009 - 19:36
LBA hooks first pancake
Ta :) just compared the downsized with original...I seem to be munting the sharpness still. Do people upload whole image to flickr and let it downsize it or do it first in their editing prog ? It was really dark in there :shock: I was amazed how good nearly all the iso 800 1/10sec pics are. ...
Posted by Transit on 16/02/2009 - 11:38
vario macro lens
Has anybody seen or used one of these? I have been loaned this one. It is a M42 screw mount with a fixed focus, that appears to be 160mm from the sensor on the K20d, leaving a working distance of around 100mm. The image below was taken with the lens set to f4. Hopefully the weather w...
Posted by jon.dc on 13/02/2009 - 09:44
50mm A 1.7mm
Should I be inputting the 35mm equivalent, or just putting in 50mm. For a 50mm lens you input 50mm. The focal length of a lens does not change when you move it from a film body to a digital body. Only the angle of view (AOV) changes but most people can relate more easily to the focal length compa...
Posted by Mannesty on 14/02/2009 - 00:24
55mm ??
Hi All SRS sent me an e-mail Monday, got back to them Tuesday and my DA*55 arrived this morning (Wednesday) just as I was leaving for work. Excellent service as always. Cameras not allowed in work so I've only been able to take a few wallpaper shots at home with flash this evening. First im...
Posted by Bob and his Pentax on 19/02/2009 - 00:06
55mm ??
nice work Bob, Very interesting that essentially the entire DA* range can handle a bigger sensor than it is currently marketed at. Pentax are clearly keeping their options open, very wise in my opinion. Edit: I've just decided that what I originally wrote is actually wrong, appologies
Posted by Mongoose on 25/02/2009 - 23:44
Tamron AF28-75mm F/2.8 XR Di
The crop factor is to do with the camera rather than the lens. It's the same with any make & model of lens, regardless of whether it's a "full frame" lens or not: 1.5 for Pentax dSLR. The camera's sensor is 1.5 times smaller than a frame of 35mm film, hence the "crop". Any 28-75mm lens on Pentax ...
Posted by iceblinker on 23/02/2009 - 13:56
16 - 45 versus 16 - 50
As for the macro specification of the 16-45, which you both probably quite rightly say it doesn't have, would you believe that I got my information from the official Pentax website. Here I downloaded and printed a pdf of the 16-45's specifications! Presumably, it's their mistake? Ooops. The term ...
Posted by iceblinker on 24/02/2009 - 15:39
