Here's the link:
http://www.pbase.com/mattmatic/smcpfa2870f4

Now I'm deciding what to remove next...

Thanks for the hints etc
I'll put a link to a couple of images I've taken of the lens - you can see the "contamination" as well as the mechanics

I actually had two of these 28-70's go in exactly the same way. The third (thanks to ebay) seems just fine and has rescued my wife's MZ10

Matt

Actually, it's three screws to remove the rear black cover. The fourth (nearest the aperture finger) holds a stop in place. Don't remove this! (It's a real pain to put back!)
Having removed the cover, I can't for the life of me see what comes next!!
Matt

Thanks Kim!
If you look from the rear, it appears to be on the second element (i.e. not the element that's touchable. If you set the zoom to 28mm, you can see the element about 1.5cm inside, held in by some kind of collar.

It appears that the rear is the only way in. I would guess that by removing the four small screws around the edge should allow removal of the black cover, and then unscrew the elements.

Let me know what you find!
Matt

Hi all,
I have an SMC-FA 28-70 f4 which has some contamination on one of the rear elements. It doesn't look like fungus (ie not streaky), but more a misty kind of thing.

I have sourced a replacement which is fine, and since this one is almost certainly beyond economical repair I was going to have a stab at a repair job (at least before chucking it in the bin!!)

Does anyone have any suggestions, maybe even an exploded diagram, that would give me a couple of clues on how to get in (and back together!).

Thanks
Matt

Patrick,

Many thanks (I'm blushing!). It was actually since going digital with the *ist-D, and learning so much from www.ephotozine.com - along with all the pro and serious amateur suggestions and help - that my quality went right up. I ran with JPG for a year and a half, while upgrading all my Pentax glass, and fiddled with RAW (using dcRAW and Adobe Camera RAW). But it wasn't until I started using Capture One seriously that things really fell into place.
I suppose it's being a computer geek (and firmware & software programmer) that enables me to get along with the digital workflow so well.

Glad you enjoyed the images, all I've got to do now is try and sell some of them! LOL!

Don - yes, it's a shame about the film emulations. That would be perfectly possible for a JPG workflow, but it's completely superfluous for a RAW workflow. I've got some serious colour profiles for the *ist-D (news will follow soon-ish I hope), and the output now is pretty much Velvia all the way

Matt

John: http://www.ephotozine.com/gallery/showlargepic.cfm?photoid=374712

Absolutely agree. I've seen some stunning work by photographers with 3 mega pixels compacts. Then there's the subject of personal style etc etc!! I'll be interested to hear your experiences with RAW too

Matt

Patrick,

You're obviously happy with JPG - so stick with it

Regarding the reviews they tend to compare the default settings of each camera, and Pentax take a conservative view of image sharpening - preferring you to do any serious sharpening on the PC.

With respect to RAW, it's not as simple as you believe Flink to make out RAW captures 12-bits per pixel (4096 values), whereas JPG captures 8-bits (256 values) per image pixel. However, JPG also throws away most of the blue channel (keeping only 11%). Now, as has been mentioned, if JPG is fine for you - that's great! But for me (and other RAW users) you just get a level of detail, dynamic range, and control you absolutely cannot get with JPG - no matter how much you adjust in-camera. You have the ability to adjust shadow and highlight detail, to push and pull the exposure by a couple of stops without noticable image degradation, to emulate different film types (e.g. Velvia), to handle wide dynamic range situations in a single shot (e.g. http://www.ephotozine.com/gallery/showlargepic.cfm?photoid=331702 ), to make fine adjustments on colour balance, to get accurate colour reproduction in the workflow (you can only approximate this in JPG), etc, etc.

But, as I said before, it takes quite a bit of effort and time to master RAW. And again, if you don't need it or aren't interested, don't bother

Just take great pictures

(Oh yes, and LOL @ Don's comment )

Matt

You'll need to give it time - RAW processing takes a little skill and practise, just like hand developing!
Matt

Patrick,
I can honestly say that RAW is so much better
There are many reasons, and most of these have been outlined in the Digital Photography section on this site. True, it takes a little while to get used to RAW, but once you start you are hooked! It's like the difference between sending your films off to get prints done by someone else, and hand developing them in the darkroom


My Capture One guide: https://www.pentaxuser.com/forum/viewtopic.php?t=1765
(Capture One isn't that hard!)

Discussion on RAW: https://www.pentaxuser.com/forum/viewtopic.php?t=1902

Comparison of RAW convertors: https://www.pentaxuser.com/forum/viewtopic.php?t=1724

TIFF, JPG, RAW: https://www.pentaxuser.com/forum/viewtopic.php?t=1692

JPG vs RAW: https://www.pentaxuser.com/forum/viewtopic.php?t=1431

BUT, if JPG gives you what you want, stick to that - it'll save you time and disk space

Hope that helps!!

Matt