[gscara]

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Thanks for your kind comments.

The Canon lenses that I am using have the old breech mount. I purchased the 400mm lens from a forum member that was already converted and was so impressed with its optics, I hunted Ebay for the 300mm L lens and found a 'bargain lens' that I had no qualms taking apart. Taking the 300 mm lens apart is fairly easy, in that I had no intention of retaining the Canon mount. In other words, the exercise was do or die and I just casually threw away everything that I didn't need!

The procedure is relatively straight forward. I removed the Canon mount and all the existing aperture coupling and control mechanism. This mechanism is not physically attached to the aperture and just pulls away from the lens assembly. This aperture control assembly is an incredible mechanical affair that is filled with springs, cogs and little metal parts. Amazing engineering!

I scanned the outline of the bottom plate and used this to fashion an 1/16" aluminum plate that bolts back to the Canon lens. This plate was easy to fashion using a wooden fret saw and some files. I epoxied a m42-pentax adapter to another matching aluminum plate and then used shims to get infinity focus. I epoxied small bolt head to the first aluminum plate and bolted the adapter to the plate that was bolted to the lens body. I used parts of the old Canon innards to connect the aperture ring to the aperture assembly.

I have read that you need to lathe2mm from the lens to ensure infinity focus. However, I found that the thin aluminum plates that I used removed more than the 2mm and hence I had to use shims.

I have not done a write up and I am unlikely to do one- just not my thing .

I was recently given a 200mm Canon macro lens that had a faulty aperture. I have dismantled this lens and its innards are similar to the older breech mount lenses. There is not a match piece-for-piece but you can see a similar aperture control arm and aperture ring. Somehow the construction of this newer lens seems 'cheaper' than the old Canon breech lens as it has more plastic parts.

Seriously good shots - i'd love to know how you modified the FD lenses to fit. Did you do a write up at all ?

AS i understood it, FD lenses were made in Bayonet mount and Breech mount - which type did you modify ?

[Squier]

Jeeeeeez!

Thanks for that - too much hassle for me i reckon. ....especially without pictures.

So the registration distance for the FD lens before modifying, is 2mm greater than Pentax K ?

[Squier]

Just got this - much easier to use M42 / K adapter

[Arjay Bee]

Some seriously good bird images here but for curiosity here are two shots of a group of Jabiru (Australian black necked storks) that allowed me to get nearish with a Schneider Kreuznach Tele Xenar 360 F5.5 (mentioned above) at about f7 or f8. Using a tripod and K20. These have been processed as the lens was underexposing and they were taken about 7.00 am with the sun yet to rise above tree tops behind the beach.

[malakola]

[pentaxman]

Here are some pictures I took this morning with my DA* 300 and Tamron 1.4X converter. They are JPEGs without any PP.




In this one, you can see the tongue sticking out. Woodpeckers have very long tongues they use to put food into their beaks.

[falconeye]

(click to enlarge or not)

Taken with a FA* 300/4.5 and a K-7

Guess, whether it is a crop or resized? Hint: the ballon is over 2 miles away ...

[redneckwes]

13.5" Cambron 400mm 6.3 telephoto lens - eBay (item 250454615397 end time Jul-05-09 18:38:59 PDT)

Anyone have a clue what I just bought??

And no, I didn't notice the rear element before, I was looking at the mount.

[Squier]

The chances are that Cambron was made for them by Tamron. At the time, Tamron was certainly making lenses for Spiratone and others, who issued a 400mm 6.3 that looked nearly identical. Pretty good by f11 by all accounts

In the shops, probably cost you $100 - so you did real good

Here's some great shots from the Spiratone copy of your Cambron:

Spiratone 400mm f6.3 - a set on Flickr

[pentaxman]

I bought a Spiratone very similar to this with the same fogging of the rear lens elements. The rear elements were very easy to remove, but I was not able to find anything that would clean the fogging. I suspect it was in the cement between the rear elements. I was able to get a refund from the Ebay seller (of course it was not sold "as is"). The bright side is that if you cannot clean it, you are only out $10.

[Squier]

Yes , i meant to say that rear lens looks pretty foggy. But if a professional camera repair shop can sort it out, and if the charge is reasonable ( $40/$50 ? ) then its still worth having , even at the higher price.

Having said that, even for $10, i'd be a little hacked off that the seller advertised this as in " great shape " though he could get away with this feeble description and simply point to the photo he supplied of the foggy end.

[redneckwes]

Thanks gents,

Even with shipping I'm out less than $20 if it's unrepairable, but I've wanted a really long tele to play with for awhile. It's worth a try.

Glad to hear that the rear element is removable, I have a last resort plan if that is glue fogging. Otherwise, I take responsibility, the picture was right there in front of me.

[Duck Dodgers]

Well, I picked up an old Spiratone Sharpshooter 400mm f/6.3, complete with original instructions, TC, close-focusing-tube (in their original boxes), and original case. All in perfect condition.

This was shot from south of the Missouri River, looking north, across to the railway yards in Kansas City, Missouri. Just a touch of sharpening added to help the old girl cut through all the down-town haze.



Pentax K10D, Spiratone SharpShooter 400mm f/6.3

[Arjay Bee]

Schneider-kreuznach 360 from hotel balcony - Cairns Esplanade in tropical sunshine

[PePe]

Here is one with the Sigma 500/4.5. Straight from my balcony.