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Forum: Pentax SLR Lens Discussion 02-06-2017, 04:39 PM  
The 60-250 screw drive mystery
Posted By bwDraco
Replies: 5
Views: 2,685
I have the exact same issue and wound up getting a D FA* 70-200mm lens to replace it. What a shame.

See Pentax DA* 60-250mm autofocus: an exercise in frustration - PentaxForums.com

Draco
Forum: Pentax SLR Lens Discussion 02-06-2017, 04:39 PM  
The 60-250 screw drive mystery
Posted By pathdoc
Replies: 5
Views: 2,685
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.
Forum: Pentax SLR Lens Discussion 05-22-2016, 01:29 PM  
How to deactivate SDM and allow for screw drive autofocus with DA* 16-50mm f/2.8
Posted By Blacknight659
Replies: 870
Views: 274,946
Hey everyone. I made a video to outline how I converted my lens. You can view it here














You Tube



. I hope it helps.

A big thanks to everyone here for the information! I wouldn't have been able to do it without you.
Forum: Photographic Technique 05-29-2011, 08:56 AM  
Defining Grey Market
Posted By Adam
Replies: 4
Views: 4,298
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
Forum: Pentax News and Rumors 02-15-2016, 08:19 AM  
Full K-1 Spec list
Posted By Kharan
Replies: 770
Views: 97,021
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.
Forum: Troubleshooting and Beginner Help 04-03-2015, 11:10 AM  
Sensor shift gone wrong :(
Posted By DeadJohn
Replies: 9
Views: 1,460
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.
Forum: Pentax SLR Lens Discussion 10-20-2010, 09:06 AM  
DA 35mm/2.4 should be called as DFA 35/2.4? - Full Frame Film Results (many photos)
Posted By Adam
Replies: 100
Views: 59,808
If not for the plastic mount, it looks like it should indeed have been a DFA!

Btw, frank- you should add your remarks to this entry: SMC Pentax-DA L 35mm F2.4 AL Lens Reviews - Pentax Lens Review Database
Forum: Pentax SLR Lens Discussion 09-24-2014, 05:22 AM  
Thoughts on what to do about broken 16-50/2.8?
Posted By Sandy Hancock
Replies: 10
Views: 1,342
I'm with him ^
Seriously.
Forum: Pentax News and Rumors 09-21-2014, 01:50 PM  
What Pentax didn't do at Photokina...
Posted By asahi man
Replies: 94
Views: 12,223
Pentax is Hyper Doomed,the only one company with a camera in every class......DOOMED :lol:
Forum: Sold Items 02-01-2014, 07:59 AM  
For Sale - Sold: Vivitar 100mm F3.5 AF MC Macro Lens P/KA
Posted By OnTheWeb
Replies: 27
Views: 5,033
Up she goes...
Forum: Sold Items 12-09-2013, 09:05 AM  
For Sale - Sold: Vivitar Series 1 105mm f/2.8 macro 1:1 w/ 'A' setting in original case
Posted By panoguy
Replies: 6
Views: 1,411
Unless you find a rare Voigtländer 125mm to buy... which will be about $2000 more! ;)
Forum: Pentax Full Frame 11-30-2013, 03:29 PM  
A7 Envy
Posted By normhead
Replies: 52
Views: 6,150
An FF K-02 would be excellent...
Forum: Pentax SLR Lens Discussion 11-20-2013, 08:28 PM  
20-40mm Limited reviewed
Posted By Pioneer
Replies: 52
Views: 7,825
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?
Forum: Pentax SLR Lens Discussion 11-27-2013, 01:04 PM  
Is there a better lens than the DA16-45 f4?
Posted By northcoastgreg
Replies: 62
Views: 7,379
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."
Forum: Pentax SLR Lens Discussion 04-21-2010, 01:11 AM  
Bokina versus Bokeh Monster, which bokeh you prefer?
Posted By JP_Seattle
Replies: 3
Views: 19,923
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.
Forum: Pentax SLR Lens Discussion 04-21-2010, 01:50 AM  
Bokina versus Bokeh Monster, which bokeh you prefer?
Posted By Caat
Replies: 3
Views: 19,923
That is a beautiful photograph.
Forum: Troubleshooting and Beginner Help 05-04-2013, 07:09 AM  
Bought a decentered 16-45...what to do :/
Posted By audiobomber
Replies: 16
Views: 4,789
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.
Forum: Pentax SLR Lens Discussion 05-01-2013, 05:40 AM  
16-45 Tilted Off Focus Plane?
Posted By wombat2go
Replies: 10
Views: 2,171
Yes, definitely confirm the problem on 2 cameras.
Also a "fence test" at wide ap is an easy way to see the problem
Forum: Pentax SLR Lens Discussion 05-01-2013, 05:31 AM  
16-45 Tilted Off Focus Plane?
Posted By wombat2go
Replies: 10
Views: 2,171
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.
Forum: Pentax SLR Lens Discussion 05-01-2013, 03:44 AM  
16-45 Tilted Off Focus Plane?
Posted By bobpur
Replies: 10
Views: 2,171
The mount rings sometimes are shimmed between the camera mount surface. You are looking at only a few thousands of an inch + -.
Forum: Sold Items 03-18-2013, 05:50 AM  
pentax a*135
Posted By unixrevolution
Replies: 1
Views: 808
Those sure are some blurry photos of photographic equipment.
Forum: Pentax SLR Lens Discussion 10-01-2012, 01:27 PM  
Who do they think they can sell the 560mm to ???
Posted By PentaxScott
Replies: 13
Views: 2,530
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...
Forum: Pentax SLR Lens Discussion 12-28-2012, 07:52 PM  
A50 1.7 aperture problems....
Posted By stevebrot
Replies: 9
Views: 1,217
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
Forum: Pentax SLR Lens Discussion 11-17-2012, 02:23 AM  
Consistent back focus with fast primes and low light? Is it me or the camera?
Posted By rawr
Replies: 10
Views: 1,962
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' ? :)
Forum: Pentax SLR Lens Discussion 11-17-2012, 02:34 AM  
Consistent back focus with fast primes and low light? Is it me or the camera?
Posted By lytrytyr
Replies: 10
Views: 1,962
OP did say "low light."
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