Search results for 'sensor cleaning' - page 128
Difference between Pentax f/1.4 and f/1.7
[quote:3496ace15f="Algernon"]It's been documented on this board previously that digital sensors can't see f/1.4 they can only see it as f/1.7 anyway Well here's proof that a sensor CAN see the differences between wide apertures. My Canon shooting buddy took some pics of his zither at 1.2, 1.4, 1...
Posted by Smeggypants on 04/02/2011 - 13:55
Difference between Pentax f/1.4 and f/1.7
That's very interesting :wink: You can actually see the curvature of field of the lens :shock: From the Exif Data The first three have exposures of 1/13th sec i.e. all the same so the lens is being seen as an f/1.7 :?: The fast lens is of absolutely no advantage. Canon must have adjusted the ISO?...
Posted by Smeggypants on 04/02/2011 - 14:25
Difference between Pentax f/1.4 and f/1.7
The DOF is related purely to the optics and is very shallow at f/1.2 and the sensor is just picking up what's there. So apart from shallow DOF there's no advantage to an f/1.2 lens :?: I don't think the argument is over whether the dof is different with under f1.4 apertures, but whether it mak...
Posted by gillbod on 04/02/2011 - 15:34
Difference between Pentax f/1.4 and f/1.7
i disagree. the contention made in the LL article is that the light coming from the edge of the exit pupil is coming from too sharp an angle for the sensor to pick it up, so the manufacturers sneakily up the iso to balance the exposure. BUT, if you see a change in the depth of field, then this li...
Posted by Algernon on 04/02/2011 - 17:16
Difference between Pentax f/1.4 and f/1.7
Whether there are differences in the actual light levels hitting the sensor or not, the two lenses the OP asked about do have different characteristics, and I did a quick wide aperture comparison a few years ago. https://www.pentaxuser.com/forum/topic/fa50mm-1-4-v-a50mm-1-7-5512 Hope that help...
Posted by Daniel Bridge on 04/02/2011 - 17:53
Difference between Pentax f/1.4 and f/1.7
Once the light has passed through the lens, within reason it can't be changed and if the lens is set at f/1.2 that will be the property of the light. You could blank off half the sensor and you wouldn't really alter it apart from only having half the photo :shock: Not really. I'm not suggesting th...
Posted by gillbod on 06/02/2011 - 00:04
Difference between Pentax f/1.4 and f/1.7
I'm not doubting the exposure issues at wide apertures, but it's still wrong to say the sensor can't see the difference between these apertures. The pics I posted earlier in the thread prove otherwise. Before my shooting buddy bought his canon 1.2 lens he asked me to send him some shots showi...
Posted by Smeggypants on 06/02/2011 - 13:25
Difference between Pentax f/1.4 and f/1.7
[quote:3496ace15f="Algernon"].... digital sensors can't see f/1.4 they can only see it as f/1.7 This is clearly untrue. Sensors can see the difference between 1.2 and 1.4, never mind 1.4 and 1.7 I've just run the following quick test which clearly shows no change from f/1.4 to f/1.8 using an Expodi...
Posted by Tyr on 06/02/2011 - 21:20
Pentax DA 55-300mm vs Pentax FA 80-320mm - Any Opinions?
One main difference between the two lenses is that the DA 55-300mm is optimised for the APS-C sized sensor, the FA 80-320mm is for 35mm sensors. I've not used the DA lens, but I had the FA one and found images quite soft at the long end where I used it most. Up to about 280mm it was fine.
Posted by Mannesty on 04/02/2011 - 19:39
Walkaround Prime?
I would have liked a wider angle than the 35mm, but the lens is superb and the only reasonably affordable AF prime. IMO the perfect prime for a cropped sensor would be a 28mm. That gives you something close in field of view to that of the 43mm Ltd on film, a length Pentax picked because they felt...
Posted by Dangermouse on 05/02/2011 - 13:44
SMC Pentax A Zoom 70-210 f/4
I've just finished cleaning my kit!...70/210 included!......turned round in my chair and shot!....nothing exciting,just a pile of washing!:D Straight out the camera!,very natural colours....and quite sharp!
Posted by beginner on 06/02/2011 - 16:38
Possibly lenses to look forward to
[quote:3496ace15f="Pentaxophile" Perhaps they'll reserve these for their ailing range of DSLRs.[/quote] That might change somewhat soon. They have a new Foveon sensor coming out with about three times the resolution of the Foveon X3 currently in use
Posted by pentaxian450 on 08/02/2011 - 21:22
Pentax smc M 50mm f4 Macro (K mount)
If it is an SMC Pentax 50mm f1.2 then buy it. Cleaning fungus from a 50mm is dead easy, although with that one I'd probably get a professional to do the job rather than wading in with my usual cotton bud and vinegar. Assuming it's built similarly to the 55mm and the M 50mm then you won't even need t...
Posted by Dangermouse on 09/02/2011 - 18:21
16-45mm F4 DA ED AL
Has anyone any experience of the Tokina 28-70mm F2.6-2.8 ATX PRO f2.6-2.8? I've had a quick search of the site which seems to suggest that its possibly soft? I always heard excellent things about other lenses in a similar focal length (Sigma & Tamron) and I note that the lens has a fairly high ave...
Posted by chrism_scotland on 10/02/2011 - 13:36
Three Shots of Contentment
If you had done it scientifically and properly you would probably be worried now! :) Indeed, I'm actually coming to the conclusion that "Dust Alert", "pixel peeping" and other borderline OCD antics are the curse of digital photography. They worry people with perceived faults which are either down to...
Posted by Dangermouse on 09/02/2011 - 18:29
Interesting article on f1.4 versus f1.8
well said John where do these strange phrases come from i was always taught from books or friends DEPTH OF FIELD not depth of focus etc Depth of focus is a proper photography term, but it differs from depth of field. IIRC It refers to the camera side of the lens, being the region in which the sen...
Posted by petrochemist on 10/02/2011 - 17:49
Interesting article on f1.4 versus f1.8
Correct, there is a certain amount of depth of focus at the film/sensor plane. This allows for some error in the location of the film/sensor plane. However, whereas smaller formats have more and more depth of field, they have less and less depth of focus. This means that smaller formats need high...
Posted by johnriley on 10/02/2011 - 18:17
12-24mm & purple fringing with K-5
I currently have a Siggie 8-16mm on back order with SRS (I originally ordered a "bargain" from ebay but the stock did not materialise - will I never learn!). Because of all the good things I constantly hear (and see) about the 12-24 I am am thinking of forsaking the 4mm difference and switching my o...
Posted by beardedwombat on 10/02/2011 - 19:25
12-24mm & purple fringing with K-5
The PF issues you're having sound sensor-related, so whether the 12-24mm has lens-related PF or not is neither here nor there really. Personally I can live with a little PF if the lens is otherwise good - the DA16-45 and Tamron 70-300 fall into this camp. Re the PF on the K5, there's some inte...
Posted by Pentaxophile on 10/02/2011 - 21:13
12-24mm & purple fringing with K-5
The K-5 does have more PF problems than the K-7. Probably better to keep a 2nd body K-7 or K20D for and pics that are likely to have PF problems. Or use lenses with very low PF. Sorry but you are totally wrong here, lenses cause PF not cameras, Jack.:mrgreen: micro lenses? on the sensor itself...
Posted by Don on 10/02/2011 - 21:55
