Search results for 'sensor cleaning' - page 112
Simple questions about 35mm lens on dslr...
First of all I would say forget all about so called crop factors since a 300mm lens remains a 300mm lens no matter what camera you put it on. The only thing that changes is the field of view since an APS-C sensor is smaller than a frame of 35mm film. Aperture does not change. Old lenses may not b...
Posted by gartmore on 05/12/2009 - 11:59
Simple questions about 35mm lens on dslr...
As Ken says it's down to the 35mm image being 'cropped' by the smaller dimensions of APS-C sensor that gives that 'apparent' change in focal length. An extremely good reference site for all things Pentax (especially lenses) can be found here
Posted by Greytop on 05/12/2009 - 12:48
Does the 18-55mm perform ok on k20d
Im popping up to SRS tommorow and have noticed this: http://www.srsmicrosystems.co.uk/1841/Pentax-smc-DA-L-18-55mm-F3-5-5-6-AL-Lens.html But I read on another thread that they had to bring out the mk II version beacause this one did perform well enough for the K20d's 14mp sensor. Is this corr...
Posted by NeilP on 15/12/2009 - 23:31
Does the 18-55mm perform ok on k20d
The AL11(2) has an extra coating on it to help make the most of the K20D's sensor. The DAL is the lightweight lens introduced with the K-M - plastic mount - no distance scale. The Exif data thinks its an AL11, which is confusing. I notice that when various magazine tests have been carried out the A...
Posted by SteveA on 16/12/2009 - 10:09
Does the 18-55mm perform ok on k20d
Im popping up to SRS tommorow and have noticed this: http://www.srsmicrosystems.co.uk/1841/Pentax-smc-DA-L-18-55mm-F3-5-5-6-AL-Lens.html But I read on another thread that they had to bring out the mk II version beacause this one did perform well enough for the K20d's 14mp sensor. Is this corr...
Posted by iceblinker on 16/12/2009 - 11:13
Does the 18-55mm perform ok on k20d
The AL11(2) has an extra coating on it to help make the most of the K20D's sensor. The DAL is the lightweight lens introduced with the K-M - plastic mount - no distance scale. The Exif data thinks its an AL11, which is confusing. It's not the coating but they have modified the lens formula. MK I ...
Posted by Anvh on 16/12/2009 - 14:18
Older manual/auto lens
Bear in mind that there is a crop factor when using film lenses on a DSLR (due to the size of the sensor). Generally you should multiply the lens by around 1.5 to find the 35mm equivalent - the 50mm becomes a 75mm on digital for example, and the 28mm a 42mm. The 135mm is a bit long therefore for...
Posted by Dangermouse on 26/12/2009 - 20:49
Older manual/auto lens
Bear in mind that there is a crop factor when using film lenses on a DSLR (due to the size of the sensor). Generally you should multiply the lens by around 1.5 to find the 35mm equivalent - the 50mm becomes a 75mm on digital for example, and the 28mm a 42mm. The 135mm is a bit long therefore for...
Posted by melness on 26/12/2009 - 20:55
tilt and shift lenses for architectural photography.
Pentax only made one shift lens (for 35mm), the "K" series 28mm shift. It goes for between 300 and 600 pounds on ebay depending on condition. There is also a shift lens for the 6x7. Unfortunately, a 28mm shift on a APS-C sized sensor is not all that useful (but I'd still like one). Canon and N...
Posted by womble on 27/12/2009 - 17:29
Cropped DA*60-250 v. Sigma 150-500 results
A short while back in a discussion about long telephoto lenses I promised to compare cropped shots from the DA*60-250 against uncropped shots from the Sigma 150-500. I managed to do a short test during the Pentax Day at Clifton Cameras on Dec 12th. You will notice from my results that the crop...
Posted by RichardDay on 27/12/2009 - 16:17
Cropped DA*60-250 v. Sigma 150-500 results
The only reason I can see to get the Sigma would be for shots that would require more than a 2x crop where the resolution drops below an acceptable level for A4 prints (3.6MP from a K20D/K-7 sensor), or for larger prints. That's probably why I prefer my 50-500mm to the 60-250mm on long shots, I ...
Posted by Mike-P on 27/12/2009 - 20:49
Cropped DA*60-250 v. Sigma 150-500 results
So are we discussing the use of shorter Pentax telephoto lenses against third party longer glass, along with their IQ? If so, here is a hand held shot on an IS body. 500mmAF Reflex. Effective FOV would be the same as 750mm due to the 1.5x factor of the sensor. I also have a 50-500 Big...
Posted by K10D on 28/12/2009 - 08:26
Cropped DA*60-250 v. Sigma 150-500 results
...they do differ due to the...different image content due to the different angular FOV. If you were shooting from the same place, then cropping the Pentax down, you would get the same field of view (and I would think, the same DoF) as the Sigma. As both field of view is wider, and the background m...
Posted by RichardDay on 28/12/2009 - 19:30
Cropped DA*60-250 v. Sigma 150-500 results
I wonder how things shape up ad the object of interest gets smaller/further away and pixel size starts to become significant. No contest past a 2x crop (equals about 3.6MP on a K20D/K-7 sensor), a longer lens will win due to the reduction in pixel count. In fact I try to keep below a 2x crop if a...
Posted by RichardDay on 29/12/2009 - 11:26
Cropped DA*60-250 v. Sigma 150-500 results
Interesting comparison Richard. I wonder how my Bigma would stack up to this test, unfortunately I dont have a 60-250 to compare it with:cry: Looking at these results however I think I could happily swap the Bigma for the 60-250, unfortunately buying the latter would make my 50-135 somewhat re...
Posted by RichardDay on 29/12/2009 - 11:58
Cropped DA*60-250 v. Sigma 150-500 results
I wonder how things shape up ad the object of interest gets smaller/further away and pixel size starts to become significant. No contest past a 2x crop (equals about 3.6MP on a K20D/K-7 sensor), a longer lens will win due to the reduction in pixel count. In fact I try to keep below a 2x crop if a...
Posted by Oggy on 29/12/2009 - 12:54
650/f8.5 Soligor
Just been out with the 28mm shift and hold my hand up "apart from seeing the image shift through the viewfinder, I dont see how it reduces convergence". It is the third time its ever been on a body. You have to make sure the body is exactly level either with a hotshoe mounted spirit level or one on ...
Posted by womble on 29/12/2009 - 22:39
Best lens for product photography?
Nice one! :) Complemented by the unedited bit of sensor dust - a vital part of the composition, I hope you'll agree. It says, "Yes, the lens really is as good as it looks, I didn't edit the picture at all." :)
Posted by ChrisA on 02/01/2010 - 23:31
Best lens for product photography?
Nice one! :) Complemented by the unedited bit of sensor dust - a vital part of the composition, I hope you'll agree. It says, "Yes, the lens really is as good as it looks, I didn't edit the picture at all." :) LOL
Posted by organicimagery on 03/01/2010 - 13:00
Was this a good price
I have a black one that I picked up for £60, as much as I have read about the slow focusing and hunting of this lens, mine is, or was, quite good and I was amazed at how quick it focused in low light. It focused quicker than the DA 55-300 but optically not as good at the long end compared to the 55...
Posted by Clarky on 04/01/2010 - 22:58
