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Forum: Maintenance and Repair Articles 5 Days Ago  
Pentax Auto Takumar 35mm F2.3 Loose barrel Fix
Posted By .a.t.
Replies: 4
Views: 397
Thanks, niceshot. It's good to know your guide is available. But for now, I think I'll just leave well enough alone.
Forum: Maintenance and Repair Articles 03-13-2019, 11:11 AM  
Pentax Auto Takumar 35mm F2.3 Loose barrel Fix
Posted By .a.t.
Replies: 4
Views: 397
Thank you for this, Pedrodelta. Your post is most helpful. And it might even motivate me to muster the courage to try to re-lube the focus helicoid on my own copy.
Forum: Welcomes and Introductions 03-08-2019, 12:36 AM  
nový člen / new member
Posted By .a.t.
Replies: 4
Views: 326
Welcome, Josef. We're glad to have you here!
Forum: Pentax Film SLR Discussion 03-05-2019, 02:22 PM  
Can't recommend Eric any longer
Posted By .a.t.
Replies: 70
Views: 6,402
Welcome, after_dark

I haven't had any repairs done by Eric and I never advanced into the nuts and bolts realm of cameras, but here's a photo of my own (inactive) ME Super :


Forum: Pentax News and Rumors 02-12-2019, 10:30 AM  
Q1 2019 Financial Reports - Pentax still not doomed.
Posted By .a.t.
Replies: 179
Views: 14,196
Using Firefox, I see a translation drop down on the right of the photoscala page itself:



Forum: Post Your Photos! 02-04-2019, 10:40 AM  
Still Life Hey I took some pictures of my new lamp
Posted By .a.t.
Replies: 1
Views: 270
That's an interesting lamp. Welcome here, trotskytown.

I often take photos of household items - particularly when I'm trying out a new to me lens.
And it's wonderful that old, wide angle lenses are wide once again on the K-1.
Forum: Pentax Price Watch 02-02-2019, 05:55 PM  
10-17mm Fisheye - Lowest price alert - $297!
Posted By .a.t.
Replies: 16
Views: 4,003
Get one. Now!
It's lots of fun to play with, but also excellent for ultra wide landscape shots.

Thanks for the alert and a great site, Adam!
Forum: Pentax SLR Lens Discussion 02-02-2019, 10:50 AM  
Mitakon
Posted By .a.t.
Replies: 19
Views: 779
You're welcome.

Okay, I understand. I hope you'll find the information you seek.






Since you bought your lens so recently, I'd guess it's a Mark II. Have you compared yours to the current B&H listing?
Mitakon Zhongyi Creator 135mm f/2.8 Mark II Lens MTK135M2BKFPK
Forum: Pentax SLR Lens Discussion 02-01-2019, 01:48 PM  
Mitakon
Posted By .a.t.
Replies: 19
Views: 779
:lol:

I guess you know much more about them than I, Prophet70!
Perhaps you could email Mitakon for some answers?

For what it's worth, in my limited experience I've found only minimal differences in performance from different generations of the same 135mm lens.

Super-Multi-Coated TAKUMAR/Super-Takumar 135mm F2.5 Reviews - M42 Screwmount Telephoto Primes - Pentax Lens Reviews & Lens Database

Vivitar (komine) Auto Telephoto 135mm F2.8 Lens Reviews - Vivitar Lenses - Pentax Lens Review Database

Having tried both the 5 & 6 element S-M-C Takumar 135 f/2.5s and the 5 & 4 element Vivitar 135 f/2.8s, I can say my modestly skilled eyes see very little difference between the results from the older and newer versions.
They're all capable of taking beautiful pictures and I think the Mitakons will too - along with the benefit of fewer aberrations than the Takumars and Vivitars would show.


[@aslyfox, I appreciate your helpful spirit]
Forum: Pentax SLR Lens Discussion 02-01-2019, 11:10 AM  
Mitakon
Posted By .a.t.
Replies: 19
Views: 779
As someone who loves 135mm lenses, I've also wondered about this Mitakon.
It appears the optical layouts differ. Version 2 has 6 elements in 6 groups, and version 1 had 5 elements in 4 groups.

Version 2 at B&H:

Mitakon Zhongyi Creator 135mm f/2.8 Mark II Lens MTK135M2BKFEF

And here's a review of version 1 (?) :
Mitakon CREATOR 135mm f/2.8 Review

The reviewer recommends the lens, but assembly quality was poor on his copy.
Forum: Pentax News and Rumors 01-13-2019, 05:35 PM  
Pentax interview collection - Pentax interview list
Posted By .a.t.
Replies: 22
Views: 1,838
Thank you!

Forum: Pentax SLR Lens Discussion 01-07-2019, 06:06 PM  
200mm F4 Takumar Dissambly Guide
Posted By .a.t.
Replies: 11
Views: 592
:p Forgive me for chuckling, cuivenion, but you're in good company. It's all too easy to get elements turned around!

If there's enough space on the side of an element, I use a pencil to draw an arrow to remind me which way is up. And if that isn't possible, I try to always set down elements so their top sides face up. Or I'll make notes about convex or concave surfaces. And taking photos of a disassembly can really be helpful.

Anyhow, it looks to me as if you have element #4 in correctly. According to the diagram, it has a noticeable convex curve on its top side. I think you'd be able to see that if you had it upside down.

I took a photo of the back side of my element #4 with the retaining ring removed. The surface is essentially flat. And note the bevelled edge.








Beautiful photo! I know very little about astrophotography, but I'd think the CA could be mitigated. You could try asking about that here: Digital Processing, Software, and Printing - PentaxForums.com
Forum: Pentax SLR Lens Discussion 01-07-2019, 11:44 AM  
SMC Takumar 50 f1.4 Clutch Problem
Posted By .a.t.
Replies: 10
Views: 502
The pictures are helpful. Thanks, simple1.
Forum: Pentax SLR Lens Discussion 01-07-2019, 10:40 AM  
DFA* 50/1.4 compared to 8 other Pentax 50/1.4 lenses
Posted By .a.t.
Replies: 20
Views: 1,563
Thank you and thank you, JPT.

I enjoyed the comparison and agree with the sentiment of the author's conclusion.
Forum: Pentax SLR Lens Discussion 01-06-2019, 09:19 AM  
HELP A Sears 60-300mm is stuck on my K-1
Posted By .a.t.
Replies: 22
Views: 1,032
That's interesting. Thanks for the photos.
Forum: Pentax SLR Lens Discussion 01-04-2019, 11:11 PM  
HELP A Sears 60-300mm is stuck on my K-1
Posted By .a.t.
Replies: 22
Views: 1,032
Ah, what a relief! That's good to know. And you're welcome.

I have a second copy of the Sears 60-300 from which I've removed the Ricoh pin. It's not the sharpest, but the focal range and close focusing make it a versatile lens.

The Samyang made Sears lenses I've used are optically decent and really good values. It's a shame so much grief has been caused by those stiffly sprung Ricoh pins.
Forum: Pentax SLR Lens Discussion 01-04-2019, 10:40 PM  
Vivitar 200mm f3.5 with 18 blades - anyone use one?
Posted By .a.t.
Replies: 5
Views: 599
Yes, it is an interesting lens. Mostly in good ways. :)

My copy is solidly built and delivers good sharpness from f/3.5. Contrast is less than a Takumar, but not bad. The iris keeps highlights rounded when stopped down, but otherwise I think background rendering is typically telephoto pleasant - but not really anything special.
My only complaint about this lens is the too long, 3.5 meter minimum focus distance.


Here's a recent sample from my back yard. It's a wide open, near MFD, straight from my Canon resized JPEG (albeit with Canon's aggressive default color / contrast / sharpening):







And this is a crop of the near, left blossom:

Forum: Pentax SLR Lens Discussion 01-04-2019, 09:29 AM  
HELP A Sears 60-300mm is stuck on my K-1
Posted By .a.t.
Replies: 22
Views: 1,032
Any luck?
Forum: Pentax SLR Lens Discussion 01-02-2019, 11:22 AM  
200mm F4 Takumar Dissambly Guide
Posted By .a.t.
Replies: 11
Views: 592
You're welcome. I'm glad you had success!
Forum: Pentax SLR Lens Discussion 01-02-2019, 04:34 AM  
HELP A Sears 60-300mm is stuck on my K-1
Posted By .a.t.
Replies: 22
Views: 1,032
Hi Botanizer,

I also have a KR mount Sears 60-300 which still has its Ricoh pin. I assume it would stick on my Pentaxes, but it's filled with fungi so I've never used it or even tried to mount it. I've kept it just because I wasn't sure what to do with it. But today it came in handy as a reference for your dilemma.
I can't recommend an easy solution, but I have some observations.






The Ricoh pin on my Sears 60-300 has a rounded tip. But I believe Not a Number has gotten to the crux of the issue.

In past Ricoh pin discussions, I recall people saying they haven't had problems with the pins on Ricoh branded lenses. And, indeed, my pin equipped Rikenon P 50mm f/2 mounts and unmounts easily on my Pentax DSLRs. So I compared the (Samyang made) Sears 60-300's pin to the Rikenon's. The tips look the same - they're both rounded. But in this case, that wasn't the issue. Rather, it was spring strength.

In an attempt to compare spring resistance, I concocted a crude mechanical experiment involving the Sears & Rikenon lenses and my K10D camera. Here's what I found:
The Rikenon 50's pin is softly sprung and the K10D's screwdrive shaft can easily displace it. To fully depress the K10D's shaft into its mount required about triple the pressure needed to fully depress the Rikenon's pin.
But for the Sears, it was the other way around. The Sears pin is very stiffly sprung. The pressure needed for the Sears is double that of K10D.
Thus, the unlucky get their lenses stuck.

Some photos (click on them for larger versions):

Sears 60-300mm KR mount - Ricoh pin and Pentax A contact labelled and the red dot is the top side of the lens (infinity mark). When the aperture ring is moved off the "A" position, the Pentax contact lowers, but the Ricoh pin stays up.



Ricoh pin on my Sears 60-300.



Underside of 60-300 mount. The tab / spring which pushes the Ricoh pin is circled.



Tab / spring unscrewed with Ricoh pin circled.







If you're willing to sacrifice your lens, either by dismantling from the front or by cutting, it appears to me you might be able to loosen the pin without harming your K-1. I used a small mirror to peek under the rim of the mount while it was attached to the lens. As far as I can tell, if the lens were cut in the vicinity of the "Sears Mod. No." ring, you should be able to access the pin's tab / spring well enough to remove the two screws holding the tab / spring in place. Or at least pry up the tab to relieve some pressure on the pin.


Viewing mirror image of Ricoh pin's tab / spring mounted on lens.




Several years ago I had a KR mount Sears 135mm lens stuck on my K10D. After I failed with feeler gauges, I just started wiggling the lens back and forth. After a while, the Ricoh pin simply broke and the lens came off. I'm sure I was wiggling firmly, but it wasn't my intent to break the pin. A small mark was left on my K10D's mount, but there was no functional damage.

I'm not advocating anyone else try brute force as a solution. YMMV and maybe I was just lucky to escape with no damage to my camera. But if I had the same situation again, personally, I wouldn't be afraid to lean on that pin a little if the alternative methods didn't work.
Forum: Pentax SLR Lens Discussion 12-31-2018, 03:33 PM  
200mm F4 Takumar Dissambly Guide
Posted By .a.t.
Replies: 11
Views: 592
cuivenion,

I've been checking my own Super Tak 200 and if your lens is built the same as mine, the silver ring assembly should screw out after some heat and / or solvent are applied.

Here's my lens:







Heat often helps me to get lenses apart. I used a space heater to warm my lens, but a hair dryer would also work. The name ring / front elements group on my lens unscrewed easily. Then, using a rubber glove to get a good grip, the silver cluster unscrewed with a bit of effort. If it's glued in place and heat doesn't help, you could try a solvent.

The silver ring cluster has an element at both the top and bottom. They're both secured by retaining rings which should unscrew. Both of my retaining rings appear to be glued in place. So you may need some solvent there.
The other remaining element is located behind the iris. But I'm not sure how you'd get access to that one.

If you get your elements free, make sure you note which sides face up. Here's a diagram from the PF lens database which may help:

Forum: Pentax Price Watch 12-13-2018, 01:01 AM  
DA* 300mm f/4 ED $796.95 at B&H
Posted By .a.t.
Replies: 1
Views: 335
Forum: Troubleshooting and Beginner Help 12-04-2018, 08:18 PM  
Sigmatel 135mm F1.8 YS Multi (How can i Open the Lens to clear it?)
Posted By .a.t.
Replies: 5
Views: 536
A professional dilettante, perhaps... ;)
Thank you, Steve.
Forum: Troubleshooting and Beginner Help 12-03-2018, 08:28 PM  
Sigmatel 135mm F1.8 YS Multi (How can i Open the Lens to clear it?)
Posted By .a.t.
Replies: 5
Views: 536
Hi Sniggi,

If you already have some experience and the right tools, this Sigmatel is relatively easy to open.

To get inside the front end, turn the focus ring to the minimum focus distance. Then you should see a small slot head screw above the focus ring. Loosen the screw just a couple turns - it doesn't need to be removed. (If the screw comes out, it'll be easy to lose and difficult to get back in place!)
With that screw loosened, the front part of the lens can now be unscrewed counterclockwise. Then you'll have access to the front elements.

With the top piece / retainer off, the front element should come out easily. Next, there's a spacer ring to lift out. And then a cemented triplet should also slide out easily.

There are also two elements behind the iris. When the iris is wide open, I believe the next element will also fall forward and out. And to get the rear element out, you'll need a spanner wrench or similar tool.

To remove the rear element, focus the lens to infinity and remove the mount adapter. Depending on which adapter you have on your lens, it might simply spin off, or it may require removing some screws first.
When the adapter is off, you'll have easier access to the retaining ring so it can be removed with a spanner.


Here's what my lens looked like when I had it apart for cleaning a few months ago:





In the picture, the second to last element is still inside the lens because I didn't need to clean it. But as I mentioned earlier, it should slide out toward the front of the lens.
And I took the aperture ring and mount off for my picture, but it's not necessary to remove them if you're just trying to get the rear element out.
Forum: General Photography 11-28-2018, 01:01 AM  
Registration distance/infinity graph?
Posted By .a.t.
Replies: 13
Views: 577
An interesting link! Thank you, Steve.
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