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02-08-2019, 04:55 AM - 2 Likes   #1
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Shaving the Pentax SMC DA 10-17mm Fisheye hood for full frame use

Hi,

I had bought the beloved Pentax 10-17mm when I had a Pentax DSLR. I now switched to Sony full frame and that lens was useable from 15mm but i was tempted to remove the hood not to see it appearing in the frame from 10mm, to get an almost circular fisheye.

So here’s a process, the highlight compared to other tutorials I had found being the information that you can remove the front element not to damage it. I’m sharing because I didn’t find that information anywhere else, and I've seen some people thinking about it on old threads.

It is obviously risky, so I decline all responsibility. Only proceed if you feel confident and are not traumatized by an eventual damaging of the lens, and if you do try, always take more time than necessary !
Also note that in Europe, you can get it done professionnaly, safer and nicer by 360pano.de

I didn’t take proper pictures in the process but I can post a few later if people are interested.

---------------------


Required tools:
masking tape
electrical soft tape
blue tack
a 33cl metal can
hacksaw with the thinnest possible metal blade (or a dremel or lather if you can)
a small metal file
general purpose glue


1) Take measurement / make marks on the hood for where to saw

The best is to saw so that the retainer ring sitting between front glass and the hood is flush (level) with the hood. Everything higher on the hood side will show on the picture.
But don’t cut too much because i’m not sure the retainer ring will fit properly after otherwise (it is quite tight and has a screw thread.on its bottom)

2) Remove front element

Use a lens spanner to grab the very thin circular retainer ring sitting between glass edge and hood internal side.
I used a curved lens spanner set with center of both arcs outside, and the very pointy ends
The two holes in the holder are very very small. The retainer ring didn’t seem to be glued, it unscrews easily if not for the friction between the lens spanner and the hood.

Place the lens spanner carefully, firmly press it down on the lens. Hold both the lens and the spanner firmly.
Give small rotating strokes to unscrew (turning counter clockwise). Don’t intend to unscrew continuously in one movement because that’s where your gesture may be to ample and you’d risk the spanner to slip and scratch the very close convex front element glass.

When you see the circular holder is free, put a microfiber cloth on top of the lens and put the lens upside down. The front and retainer ring will fall.

3) Make protections to prepare for sawing

Cut a 33cl aluminium can or similar into a band.
Measure length of the retainer ring : outside and inside, make the average and roll the can band into a tube with that diameter. Put chatterton band / electrical soft tape to keep it in shape and tape on all of the bottom edge to make it less damaging when you’ll press it into the lens.
Put a 1mm thick blue tack thread all around the outside of the bottom of that can tube (for sealing against dust).
Place this inside the lens, push the blue tack in.
This will protect the inside from all metal dust.

Tape the lens from bottom to just under the hood with masking tape.

4) Gently saw the 4 hood bits

Start gently to make a path for the blade. It goes quite fast after to saw the hood bits.
The tricky part is to saw where you want. My saw’s blade was too thick, i was lucky to cut on the right area. I had trouble making it totally flat, it’s slightly uneven and rough but functionnal.

I initially intended to use a jubilee clip to guide the saw, but the one I had was finally to wide (12mm) and couldn’t fit below the part to saw. If you find a slimmer one...

5) Vacum clean every dust bit before removing protections.
Remove protections

6) Put the lens facing down and gently grind the edges of the sawed hood to make it more even. Go gently on the inside part of the cut hood because you need to be able to put the retainer ring in after.
Gently vacuum clean the inside.

7) Put back the front element in the retainer ring and in the lens
Remember the glass goes into the retainer from the inside of the lens, and the retainer’s outside/up side is the one with the holes for the lens spanner.
Put the lens down toward the front element assembly.
Hold it and put it front side up, screw clockwise by hand first, finish with the lens spanner. Be more careful than for disassembly because you don’t have the edges of the hood anymore to help hold the lens spanner in position.

8) Vacuum everything again, you don’t want any metal dust when cleaning the glass after.

9) Modify the lens cap
Grind the rough edges of the hood bits you sawed and glue at least the longest 2 bits to the inside of the lens cap.
You can tape some adhesive band inside the lens cap on the edges so it’s a tighter fit, which will compensate the shorter contact length of the cap with more friction when mounted on the lens.

10) Enjoy. I find it quite fantastic to have a lens that can both be almost circular fisheye and full frame diagonal fisheye !

P.S.: Some might be shocked i modified such a nice lens. i hesitated, but my lens already had lost resale value since the autofocus had became inoperant on my pentax (it was making the autofocus noise but nothing was moving).

P.S.2: not a native english speaker, sorry for the grammar and spelling mistakes


Last edited by Pattok; 02-08-2019 at 10:35 AM.
02-08-2019, 05:37 AM - 2 Likes   #2
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(somebody else read this and tell me if it came out OK at the end)
02-08-2019, 06:06 AM   #3
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Hi, Pattok, welcome. That's quite an operation: I'm sitting here looking at my 10-17 Fishy and every sphincter in my body is automatically contracting violently at the thought of taking a saw to it... :O
02-08-2019, 07:03 AM   #4
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Hehe... i can understand that. I think it was my most costly lens when I was on Pentax cameras.
I had been itching for more than a year before going to action.
If it didn't have non functional autofocus, I wouldn't have done it myself like that.

But the view on full frame is quite impressive now, it has more value for my use, I won't sell it !

02-08-2019, 07:27 AM   #5
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... would be fine to see your work!
02-08-2019, 10:19 AM - 1 Like   #6
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Here are some pics

Front element removed




End result, you can see the 2 holes in the retainer ring on the first one, and that it would deserve finer filing and a small paint job on the edges on the second shot,




A test shot at 10mm

02-08-2019, 09:07 PM - 1 Like   #7
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The Tokina 10-17 is exactly the same lens, and comes in versions with and without the hood.

I use my Pentax 10-17 on the K1. There is no vignetting from 14mm upward. The full circular fisheye effect would be nice, but I'm not brave enough.
02-09-2019, 07:51 AM - 1 Like   #8
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Thank you very much, I think it is a nice idea. I did it myself:

http://www.criseis.ruhr.de/bilder/pentax_10mm/zoom1.jpg

http://www.criseis.ruhr.de/bilder/pentax_10mm/zoom2.jpg

I think it looks nicer if you use a grinder and not a saw.

The next step is black painting and thinking about a better lens cap, because I think the old cap will touch the lens now.

Olaf

02-09-2019, 08:28 AM   #9
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QuoteOriginally posted by Paul the Sunman Quote
The Tokina 10-17 is exactly the same lens, and comes in versions with and without the hood.

I use my Pentax 10-17 on the K1. There is no vignetting from 14mm upward. The full circular fisheye effect would be nice, but I'm not brave enough.
I also fall into the camp of not brave enough. I have a very good Delta drill press....but while I applaud those who have the skill to expertly cut away the hood on the 10-17 with no damage...I'm not one to give it a try.
02-09-2019, 12:55 PM   #11
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QuoteOriginally posted by Darkover Quote
Thank you very much, I think it is a nice idea. I did it myself:

http://www.criseis.ruhr.de/bilder/pentax_10mm/zoom1.jpg

http://www.criseis.ruhr.de/bilder/pentax_10mm/zoom2.jpg

I think it looks nicer if you use a grinder and not a saw.

The next step is black painting and thinking about a better lens cap, because I think the old cap will touch the lens now.

Olaf
That definitely looks better. I didn't have such a tool in reach.
The borders on your 10mm samples are also better because mine show some slight irregularities in parts I didn't shave enough.

---------- Post added 02-09-19 at 08:59 PM ----------

QuoteOriginally posted by Paul the Sunman Quote
The Tokina 10-17 is exactly the same lens, and comes in versions with and without the hood.

I use my Pentax 10-17 on the K1. There is no vignetting from 14mm upward. The full circular fisheye effect would be nice, but I'm not brave enough.
Yes it's the same indeed.
Maybe pentax will update with a no hood version. It's quite nice with the zoom to have semi circular to full frame fisheye.
02-09-2019, 11:35 PM   #12
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QuoteOriginally posted by Pattok Quote
It's quite nice with the zoom to have semi circular to full frame fisheye.
For someone who did not own this lens I would recomend to buy the 14mm/2.8 Samyang first because it is better usable in everyday projekts.
But I agree there is some fun in using the fishey zoom, because the look&feel of the picture change MUCH if you zoom a little and move the camera, too. When I took the last picture (zoom9) from my car I used this so the camera show a car that has to be build from BMW in the future. :-)
It was also an interesting experience to walk around with only the 10-17 on my camera and think what can I do with only this lens and nothing more. I thing I will repeat it.

Olaf
02-10-2019, 12:04 AM - 1 Like   #13
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I've given some serious though about this in the last few years, and IMHO it's not worth the bother and risk. The amount of usable image gained is minimal unless you really like circular images. And you don't even get a full circle.

The hood is made to a very high tolerance of what the crop image sees, and the corners of the full image circle @ 10mm correspond almost exactly to the corners of the APS-C frame.

This was taken over three years ago on a film SLR @ 10mm. Use the concentric circles on the inside of the hood to work out how much more image you'll get.

DA10-17 @ 10mm MFD film
07-05-2019, 09:46 AM   #14
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Not brave enough to do this to my 10-17. Since the hood/retaining ring comes off - couldn't someone 3D print a replacement part without hood?
thanks,
barondla
11-10-2019, 03:43 AM   #15
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I have shaved my Px 10-17 too.
Here are photos of shaving process :-)

Pentax 10-17 - before shave


Pentax 10-17 - protecting front lens


Pentax 10-17 - protecting lens body


Pentax 10-17 - adjustment of milling cutter height


Pentax 10-17 - first hood part is removed


Pentax 10-17 - all hood parts are removed


Pentax 10-17 - front lens protection removed


Pentax 10-17 - front silver border is painted by black color


Pentax 10-17 - front silver border is painted by black color


Pentax 10-17 - cap adjustment

Last edited by alda78; 11-10-2019 at 09:36 AM.
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