Forum: Pentax SLR Lens Discussion
02-06-2017, 04:39 PM
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Forum: Pentax SLR Lens Discussion
02-06-2017, 04:39 PM
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I don't like your chances, but good luck anyway!
I always thought the focal length was reported by an analogue to digital conversion of some sort of potentiometer signal (or possibly very narrow discrete steps) as the focal-length helicoid was spun up or down towards narrow or wide angle. Maybe Pentax does it differently; I don't know.
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Forum: Pentax SLR Lens Discussion
05-22-2016, 01:29 PM
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Hey everyone. I made a video to outline how I converted my lens. You can view it here You Tube |
src="https://www.youtube.com/embed/gpfcEebrBSs?controls=1" allowfullscreen> |
. I hope it helps.
A big thanks to everyone here for the information! I wouldn't have been able to do it without you.
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Forum: Photographic Technique
05-29-2011, 08:56 AM
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If you know someone in the us, you can take advantage of the US warranty even if the item was shipped outside the US, right?y
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Forum: Pentax News and Rumors
02-15-2016, 08:19 AM
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The problem is that manufacturers don't really make their own shutters, but typically source them from Copal or Seiko. If you look for LensRentals' camera teardowns, you'll see that Canon, Nikon and Sony, at the very least, get their shutters from those two companies. I don't know about Pentax, but I'd be very surprised if they were any different, since shutters are precision mechanisms (comparable to analog watches) that require considerable expertise in a field that has no other direct application in photography. So I'd blame the provider, or Ricoh's management for choosing a different set of compromises than you or I would've (faster X-sync at the expense of durability or cost). Because that's how it is: focal plane shutters need to suffer extreme stresses, perform within microscopic tolerances, be perfectly sealed against light ingress, have the curtains be very thin, and also perform reliably over the course of thousands of shutter cycles. And, most importantly, can't just be made of unobtainium, or take a gigantic amount of space inside the camera. I'd say that Ricoh, in this case, simply decided to go with the rated 300,000 thousand shutter cycle life, while having heavier curtains that simply can't travel as fast as those found in other similar cameras.
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Forum: Troubleshooting and Beginner Help
04-03-2015, 11:10 AM
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Note that when SR is turned off, the SR motors are still activated to hold the sensor in a fixed position. That's why some Pentax cameras make a "clunk" when the camera is moved while off; it's the sensor shifting around while the motors have no power.
If an SR motor is broken then it might cause shake even when SR is turned off. To test, disable SR and put the camera on a sturdy tripod. Use the 2 second delay timer or a remote shutter release to prevent shake. Take a dozen pictures and pixel peep check for a problem.
Take some images in landscape and some in portrait orientation to see if the blur direction rotates 90 degrees.
Also, try a different lens because maybe one of the lens elements might have come loose inside. A lens alignment problem could create symptoms that look like camera shake.
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Forum: Pentax SLR Lens Discussion
10-20-2010, 09:06 AM
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Forum: Pentax SLR Lens Discussion
09-24-2014, 05:22 AM
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I'm with him ^
Seriously.
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Forum: Pentax News and Rumors
09-21-2014, 01:50 PM
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Pentax is Hyper Doomed,the only one company with a camera in every class......DOOMED :lol:
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Forum: Sold Items
02-01-2014, 07:59 AM
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Forum: Sold Items
12-09-2013, 09:05 AM
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Unless you find a rare Voigtländer 125mm to buy... which will be about $2000 more! ;)
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Forum: Pentax Full Frame
11-30-2013, 03:29 PM
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An FF K-02 would be excellent...
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Forum: Pentax SLR Lens Discussion
11-20-2013, 08:28 PM
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Well...they certainly seem more impressed with the new Sigma. I certainly hope this isn't the start of a trend. It would be a real shame for another potentially great Pentax product to get thrown to the wolves because it isn't the cheapest...the fastest...the widest or whatever. Of course, that has never happened before...has it?
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Forum: Pentax SLR Lens Discussion
11-27-2013, 01:04 PM
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Yes, there are better lenses, but better in what way? What do you need that the 16-45 isn't giving you? WR? Silent focusing? Greater zoom range? More resolution? Better microcontrast? Better color rendition? Faster aperture.
I have a copy of the DA 16-45. I bought it instead of the DA 16-50 largely because of the SDM issue (I otherwise considered the DA 16-50 better optically based on images I had seen from both lenses). Although the 16-45 is a very nice, capable lens, with some of the best corner to corner sharpness I've ever run across in a zoom lens (particularly at the wide end), I found it wasn't keeping up with my other glass. The images I was getting from it didn't have quite the same vividness and brightness of color as my other lenses. It was most noticeable in prints, which just didn't have the same visual impact. So I purchased the FA 20-35 as an upgrade.
There are many other lens that, like the FA 20-35, are better, at least in some ways, than the 16-45. For WR, there's not only the 16-50, but the new DA 20-40 and the DA 18-135. Both Sigma and Tamron, along with Pentax, offer faster, f2.8 standard zooms. Pentax offers four standard zooms with focus moters: the DA 18-135, the DA 17-70, the DA 20-40, and the DA*16-50. While none of these alternatives are likely to offer significant more resolution (the DA 16-45 is pretty good in that respect), some of them (at least the Pentax star and limited options) will likely give you images that have bit more contrast and "pop."
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Forum: Pentax SLR Lens Discussion
04-21-2010, 01:11 AM
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I have never seen anything that has more desirable bokeh than the Vivitar Series 1 90mm "Bokina".
I have seen several lenses that come close. The latest one that really impressed me was the Vivitar 85mm f/1.4 (made by Samyang) that sells for under $350 new.
It was a well-built solid feeling manual focus lens with "A" contacts.
Very similar focal range to the Bokina, a little "faster", and a lot easier to find than the "Bokina"... but I wouldn't call it a Bokina replacement.
I have never used the Pentacon 135mm but I can say that I don't really care for that focal range on a APS-C DSLR camera.
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Forum: Pentax SLR Lens Discussion
04-21-2010, 01:50 AM
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That is a beautiful photograph.
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Forum: Troubleshooting and Beginner Help
05-04-2013, 07:09 AM
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Is this a new purchase? No right of return?
My 16-45 was sharp as hell when new. One day after a couple of years of heavy use and maybe a fall, photos were all soft. I sent it to Pentax Canada for repairs. It came back sharp as ever and the barrel is tighter than when it was new, no wobble at all. I think they charged me about $130. They quoted before making the repair.
It's well worth sending it in IME. You can't sell it in that condition anyway, not if you have a conscience.
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Forum: Pentax SLR Lens Discussion
05-01-2013, 05:40 AM
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Yes, definitely confirm the problem on 2 cameras.
Also a "fence test" at wide ap is an easy way to see the problem
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Forum: Pentax SLR Lens Discussion
05-01-2013, 05:31 AM
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I was able to correct an old zoom that had a side to side register alignment problem and it is quite good now.
(reposted images)
Before: showing right side is sharp and left is not focussed https://www.box.com/s/98e8559cccbd0d0e83a4
With some tests it is possible to detemine which way to correct.
this was a repetitive process involving partial re-assembly and test shots
Dismantle, Very carefully hand grind the high side on a fine flat stone with water. This will take the register past infinity. https://www.box.com/s/edb6960a3a2a8ae738f2
Then shim back to infinity using a gasket made of cooking parchment ( 0.02 mm, 0.8 thou inch) between the original brass shims
After tuning: https://www.box.com/s/8bd668f7368a02e3dc68
However if the lens has any reasonable value I would recommend a pro repair where hopefully, the bad parts would be replaced.
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Forum: Pentax SLR Lens Discussion
05-01-2013, 03:44 AM
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The mount rings sometimes are shimmed between the camera mount surface. You are looking at only a few thousands of an inch + -.
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Forum: Sold Items
03-18-2013, 05:50 AM
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Those sure are some blurry photos of photographic equipment.
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Forum: Pentax SLR Lens Discussion
10-01-2012, 01:27 PM
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While this lens isnt on my wish list, I dont think the pricing is quite as extreme as its made to be. That may all change when the lens reaches the hands of consumers, but as of right now, comparing it to its actual competition of prime lenses between 500mm and 600mm and f/4-f/5.6 we get the following lenses:
Canon 500mm f/4L EF IS II USM Lens - $10499.00
Nikon AF-S NIKKOR 500mm f/4G ED VR II AF Lens (Black) - $8399.00
Sigma 500mm f/4.5 EX DG APO Autofocus Lens (Various Mounts) - $4999.00
Sony500mm f/4.5 EX DG APO Autofocus Lens - $12998.00
Canon 600mm f/4L EF IS II USM Telephoto Lens - $12999.00
Nikon AF-S NIKKOR 600mm f/4G ED VR AF Lens - $9799.00
Suddenly $6999.95 for a 560mm f/5.6 doesnt seem too bad. Yes, its a half to a full stop slower than some of the competition, but aside from the Sigma, its at least $1400 cheaper than the next lens in this area. If the image quality is similar to the competition, I dont think that $6999.95 is unreasonable to ask for the lens. Additionally, Im sure the pricing of the lens will level out with after 6-12 months. I say we wait to pass judgement until image results are seen...
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Forum: Pentax SLR Lens Discussion
12-28-2012, 07:52 PM
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Because the aperture ring represents a mechanical "stop" while the body uses a more imprecise movement of the aperture actuation lever (x-number of mm travel per f/stop). The two are only approximately equivalent.
Steve
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Forum: Pentax SLR Lens Discussion
11-17-2012, 02:23 AM
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Low light = low contrast = any AF is going to be challenging (except for the K-5II).
I get the most reliable low-light AF using centre-spot focus only. And as some have suggested, the AF can usually be 'trained' to a degree when the lighting gets bad to work more effectively.
Also note this from Nikon:
Also - shooting street at almost wide-open:eek:
What happened to the old adage 'f8 and get close' ? :)
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Forum: Pentax SLR Lens Discussion
11-17-2012, 02:34 AM
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