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Forum: Non-Pentax Cameras: Canon, Nikon, etc. 04-20-2020, 03:16 AM  
Reversibly modifying infinity focus on Chinon 28mm lens to fit Zhongyi Lens Turbo II
Posted By TDN
Replies: 0
Views: 292
Hi,

I recently got a Lens Turbo II to use with my Sony NEX-6, in the hopes of getting some true wide-angle out of my Pentax primes. Unfortunately, both of the Pentax 28mm lenses (M and K) I have exhibited rear-element-collision with the adapter, so no infinity focus and the risk of damaging the lens as well as the adapter.

However, I do also have an Auto Chinon 28mm f2.8 lens I got with a camera set. This one had the same problem, but to a much lesser degree than the Pentax lenses. The collision between the elements happened just barely before infinity focus was reached.
My only use for this lens would be with the lens turbo (The better Pentax 28mm's fit my K50, but aren't really wide-angle on APS-C), and I can't resell it because it has oily aperture blades, even after I did an amateur repair. So, I decided to experiment with the lens a little to see if I can't make it usable on the Lens Turbo, with succes! :cool:

I'm sharing the process on here, since it might be applicable to other older lenses as well. I wouldn't try this with a modern and/or expensive lens.

DISCLAIMER: TRY AT YOUR OWN RISK. Don't hold me responsible if you mess up expensive glass :hmm:

I've attached illustrations for all of the steps.

0. Before you do anything, put your lens on the Lens Turbo II, and put the rear cap on the complete assembly of adapter + lens, so you can put it upright on your work surface.

1. Open up the front of the lens by screwing off the vanity plate. Usually this is done using a rubber thingy to create friction with the plate, and it simply screws off counterclockwise. In other cases a spanner wrench specifically for lens repair is needed, but not with this lens.

2. Take off the metal flange covering the focus mechanism. In this case it was done with 2 tiny screws. (1.5mm flathead)

3. Next we're going to loosen the focus ring. It's a good idea to mark the current position of the ring using a small scratch/punch at this time. No one will ever see this unless they open up the lens themselves. Once you've marked it, partially loosen the 3 screws holding the focus ring in position, but don't take them out! Once you can turn the ring loosely without the focus mechanism adjusting, you're good. It doesn't take much, maybe 1 full turn for each screw. For this lens I used a PH00 screwdriver.

4. Now you can put the loose focus ring in the correct position. Be sure to check that everything still lines up after the next step as well.

5. You can now use your screwdriver to softly turn the focus mechanism to the point where the lens elements collide. You can distinctly hear the difference between the lens "ticking" to max focus, and the soft "thud" of the glass elements colliding. Once you're certain you've turned it to where the elements collide, turn the focus mechanism back a tiny bit, so the elements no longer collide. Then you can tighten the 3 screws again (make sure the infinity mark on the ring in step 4 still lines up!).

That's it, you're as good as done! Before you re-assemble the lens in reverse order, you can do a quick test on the camera to see whether the focus is alright.

You now have a lens that technically doesn't really focus entirely to infinity, but at least it handles as if it would, and it can't damage the glass of the Lens Turbo II or the lens.
Whether you can actually get far-off objects/landscapes in focus will depend on how much you had to adjust the focus mechanism.
Since the difference was very small on my lens, I honestly don't really notice it, especially when stopped down.
The good thing about this is that it's fully reversible if you marked the original position of the focus mechanism in step 3. So if you ever do get that Pentax full frame, you can adjust the lens right back and toss your LT2 :p.

I'm pretty happy with the results. I'll see if I can take some sample pictures later.

Tom
Forum: Non-Pentax Cameras: Canon, Nikon, etc. 04-17-2020, 06:37 AM  
Lens Turbo II PK-NEX First Impression
Posted By TDN
Replies: 41
Views: 18,800
I'm aware this is an old thread, but couldn't find any other posts documenting Pentax lens compatibility with the Lens Turbo II.

I got mine today, as part of my hopes to get full-frame-like wide-angle using old lenses, but alas, all 28mm lenses I tried seemed to make contact with the rear element...
Well, at least my fisheye worked, which is nice.

Update: I originally labeled the Auto Chinon MC 28mm as "not working", but I have since modified it in a reversible way to make it work with the LT2. I'll start a new thread about how to do that.

Lenses I tested & results:

Working
Pentax K 17mm F/4 fisheye
Pentax K 55mm F/1.8
Pentax-M 135mm F/3.5
Pentax-A 50mm F/1.7
Auto Chinon Zoom MC 35-200mm F/4-5.6

Basically any lens where the rear element does not protrude from the mount should work fine.

Not Working fully (not focusing to infinity due to rear-element-collision)
Pentax K 28mm F/3.5
Pentax M 28mm F/3.5

Working after reversible focus modification (modification process is explained here)
Auto Chinon MC 28mm F/2.8

I'm not ready to void my warranty yet & try the shimming method. First impression of this adapter is that it's flimsy enough as it is...
Forum: Pentax SLR Lens Discussion 11-27-2015, 06:31 AM  
How to disassemble SMC Pentax-FA 100-300mm F4.7-5.8 front element?
Posted By TDN
Replies: 4
Views: 1,280
Just a small follow-up on this:

I ended up disassembling the lens with only minor scratches to the paint of the filter ring. You really need to be careful with this one, even with lens spanners.
For future reference: you need to insert the sharp ends of the lens spanners into the two small holes next to the front lens element to screw the actual element a bit further down so the retainer ring is loosened. Then you need to use the flattened ends to carefully screw out the ring from the filter thread. The front element then simply screws out of the filter thread as well. You then have access to the screws to take the lens apart if needed. However, it turned out my fungus was limited to the back of the front element. After wiping it off with a lens cloth and reassembling, the lens performs beautifully!
Forum: Pentax SLR Lens Discussion 08-10-2015, 08:36 AM  
How to disassemble SMC Pentax-FA 100-300mm F4.7-5.8 front element?
Posted By TDN
Replies: 4
Views: 1,280
Cool, thanks! I had no idea what to look for.

Spanners are on their way :)
Forum: Pentax SLR Lens Discussion 08-10-2015, 06:55 AM  
How to disassemble SMC Pentax-FA 100-300mm F4.7-5.8 front element?
Posted By TDN
Replies: 4
Views: 1,280
Hi,

I recently picked up a SMC Pentax-FA 100-300mm F4.7-5.8 lens for a good price together with some other stuff, from someone who didn't know much about cameras. I figured I would have some fun with it on an upcoming trip, and then sell it on as I don't use long telephoto that much.

It works just fine, and seems sharp enough, but there's one annoying detail the seller didn't see before shipping it to me: it's got some minor fungus growing on the side of the glass right behind the front element. I bought it as is, and can't return it (nor do I want to).
It seems to be isolated to that element and is not that severe, but it seriously affects the value of the lens, the faith I have in it, and it's just plainly annoying.

Since it's isolated to the 2nd element alone, I was wondering if anyone if it would be easy to take off the front element of the lens. If I can get that one off, I'm pretty confident most the fungus will just come off with some wiping. Then I can resort to some days of UV-exposure and I think the lens will be fine.
Has anyone here ever done that?

I can see two small notches next to the front glass, and was wondering if that's how you get it out. If so, what tools should I use for this?
I don't have any pictures of the front side of the lens, but there is one in this for sale post. You can see the notches right next to the glass on the top and bottom of the 2nd picture.
The fungus on my lens is definitely before the glass element that is held in with the three visible screws. If it were any deeper in, I wouldn't try disassembling myself...

Any further tips are welcome.
Thanks in advance!

- Tom
Forum: Flashes, Lighting, and Studio 08-04-2009, 11:06 PM  
one flash, corded. still have good photos?
Posted By TDN
Replies: 19
Views: 5,147
There's lots of stuff you can do with 1 flash!
If you balance it with the ambient it can be a real extra value to your shots.

Most important things to have in my opinion:
- something to trigger it wirelessly
- an umbrella

Some of mine:





And this one even won a prize ;)



Tom
Forum: Flashes, Lighting, and Studio 07-28-2009, 09:46 PM  
Metz 48 flash noob! Please help :)
Posted By TDN
Replies: 19
Views: 5,267
oh sorry, "idd" is an abbreviation for "indeed", I use it so often it has become automatic :)

glad to help!
Forum: Pentax Camera and Field Accessories 07-28-2009, 09:44 PM  
Cactus V4
Posted By TDN
Replies: 73
Views: 26,506
I have the exact same thing on my K10D with 1/160 shutter speed with the V2s triggers.
With 1/180 there is no problem though.
So I think it has something to do with the 1/3 EV steps instead of 1/2 EV steps setting on the K10D...

Tom
Forum: Flashes, Lighting, and Studio 07-28-2009, 09:08 PM  
Metz 48 flash noob! Please help :)
Posted By TDN
Replies: 19
Views: 5,267
First off, you made a good choice for a flash! I have the same one since a few weeks, and after having the Sigma counterpart (pricewise), the 530 ST, I have to say that this one is just 10x better!



You set the camera to the wireless flash mode idd. Then you open the popup flash.
To set the flash to wireless slave mode, push both the + and - buttons together. You will see a few option pass the LCD screen. Keep pushing both buttons until you see "SL off" on the screen. Then push the + button only, so that it changes to "SL on".
The red autofocus assist light on the front of the flash should start blinking now. Your flash is now in wireless slave mode :)


No. :p

Have fun with the flash!

Tom
Forum: Flashes, Lighting, and Studio 06-29-2009, 02:12 PM  
Off Camera Flash
Posted By TDN
Replies: 2
Views: 1,485
sounds like you were trying to shoot faster than 1/180, which won't work on pentax cameras.
Can't tell you how many times I've made the same mistake... :)
Forum: Flashes, Lighting, and Studio 06-29-2009, 02:08 PM  
Use two off camera flash
Posted By TDN
Replies: 3
Views: 1,621
the af500 won't be in TTL, but other than that i don't see why that wouldn't work.

If you really want to play it safe, you could always use a wireless or optical trigger instead of the sync-cord.

i doubt that any of those flashes has an unsafe trigger voltage, so my guess is that there is no harm in trying.
Forum: Pentax Camera and Field Accessories 06-29-2009, 02:02 PM  
Strobist Bootcamp II
Posted By TDN
Replies: 10
Views: 2,812
:) Thanks. Fun to see a thread about it here. I can still hardly believe I won, but the speedight pro kit is on its way :)

I'm really loving that combo, the K10D with the 50mm.

Shows that for realistic purposes, Pentax is at least as good as any other brand, and that mister DH doesn't care about the label on your camera, but about the results :)

Some great photos on the sites posted above here, very nice.

Tom
Forum: Pentax Film SLR Discussion 05-24-2009, 02:45 PM  
Pentax K2 DMD
Posted By TDN
Replies: 4
Views: 19,491
I picked this one up for a bargain together with some lenses.
Haven't done much shooting with it, I'll update this when I have.

Pros:

Seems like a very sturdy and rugged camera. I'm pretty confident this thing would survive a war ;)

A lot of features, especially for a camera this old. Things like DOF preview, self-timer, X-sync socket, manual as well as automatic lighting, ... (see chart above)

Winder available, yet hard to find. Once you attach it it'll give you 2 fps.

These aren't as easily found as some other models, so if you see one definitly check it out. Also, this one came with a 50mm 1.4 as standard lens, which only shows that this camera was aimed at the more advanced photographers. So if you see one 2nd hand, be sure to check out the lens.

cons:

The ASA dial is extremely awkward to use. It's positioned around the lens mount, which is a very illogial place, especially if you compare it to the ease of the mechanism on the K1000 (at the shutter dial).
Takes a while to get used to, and always seems to block when you're in a hurry ;)

Compared to models as the K1000, it's pretty heavy. I can imagine that combined with the grip, this thing might get a little too heavy for some people.

Doesn't have a TTL flash mechanism, but I'm not an expert in flash photography with film, which is why i avoid it, so this doesn't bother me.
Conclusion:

Nice, sturdy camera, which is built to last. Apart from some weird design choices that were corrected in later models, this is a camera that'll be a pleasure to use even after so many years.


These were just my initial impressions, but I'll update this once I have some more experience with this camera after this summer.
Forum: Pentax News and Rumors 01-13-2009, 01:59 PM  
New dSLR camera body patent?
Posted By TDN
Replies: 38
Views: 7,542
Images are of a *ist D body.
Forum: Pentax SLR Lens Discussion 09-09-2008, 08:10 AM  
JUPITER-9 85mm
Posted By TDN
Replies: 27
Views: 5,258
The Jupiter works with a pre-set aperture. This means you turn 1 ring in the front of the lens to the aperture you want, and turn another to manually close the diaphragm to that aperture.

Don't worry, it will have markings, you just can't see them on the picture.

I have the same lens and am very pleased with it. A little soft at f2, but very nice at f2.8

Tom
Forum: Pentax SLR Lens Discussion 09-08-2008, 08:18 AM  
Need info: Sigma 28-70mm f2.8 EX DF
Posted By TDN
Replies: 11
Views: 12,701
I have the non-DF version of this lens.

270USD is a bit much i think, but if you can get it for 200-225 USD don't hesitate!

It's my main lens for photojournalism. I've used it at concerts, events, for portraits, etc. and have gotten great results!

A few examples:






Tom
Forum: Lens Clubs 09-07-2008, 02:43 PM  
Fisheye Fever Club -- Flaunt your fisheye photos!
Posted By TDN
Replies: 3,692
Views: 660,501
Sorry, hotlink protection was on at my server, i forgot to add pentaxforums to my safe list.

Should be fixed now :)

Tom
Forum: Lens Clubs 09-07-2008, 01:31 PM  
Fisheye Fever Club -- Flaunt your fisheye photos!
Posted By TDN
Replies: 3,692
Views: 660,501
Thanks, I was lucky to find one :)

A few more:
(the 3rd one is one of my favourite shots!)






Forum: Lens Clubs 09-06-2008, 05:42 PM  
Fisheye Fever Club -- Flaunt your fisheye photos!
Posted By TDN
Replies: 3,692
Views: 660,501
With the Pentax K 17mm f4 fish-eye

Picked up this lens for a bargain-price this summer, great alternative to the zenitar.
I also tried it on a film camera...man that's wide! :)

With my ist DL:


Tom
Forum: Pentax SLR Lens Discussion 09-04-2008, 07:07 AM  
Poll: 50mm 1.4, 40mm 2.8, or 35mm 2?
Posted By TDN
Replies: 24
Views: 3,622
A 50mm is something every photographer should have in his/her camera bag, in my opinion...

So, the 50mm f1.4 :)
Forum: Pentax News and Rumors 08-27-2008, 08:55 AM  
What and how to compete against the 50D and D90 etc.??
Posted By TDN
Replies: 7
Views: 2,676
Let's make ricehigh crispies instead!:D
Forum: Pentax News and Rumors 02-27-2008, 09:37 AM  
K20D VS Canon 40D High ISO (Not 56K Friendly)
Posted By TDN
Replies: 42
Views: 37,738
Nikon D300: € 1575.00

Pentax K10D: € 615.00

Pentax K20D: € 995.00

For almost €1000 difference with the K10D, the D300 better be better...
The fact that the 2 are even being compared is a compliment to Pentax ;)

I have no doubt the K20D will be able to hold its ground next to the big guns.

Tom
Forum: Pentax News and Rumors 02-10-2008, 03:51 PM  
A few K20d samples from Edvinas
Posted By TDN
Replies: 8
Views: 2,638
Thát is ISO 1600? I had to check the EXIF to believe it.
wow...that is impressive.

Tom
Forum: Sold Items 02-06-2008, 10:31 AM  
For Sale - Sold: FS: Tamron 80-200 f2.8 SP & KA mount
Posted By TDN
Replies: 7
Views: 3,480
ahh too bad you live in the US, or I would jump on this one.

Now I would have to pay a lot extra for VAT etc...

Good luck with the sale!

Tom
Forum: Pentax News and Rumors 01-30-2008, 03:08 PM  
Pentax used to know how to do adverts
Posted By TDN
Replies: 8
Views: 2,635
That is the most awesome thing I've ever seen! Makes me actually want to buy one!:lol:

That 2nd clip from the original post is pretty cool too :)

I say remake these with a K20D!

Tom
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