[David&karen]

Our DFA 100 Macro has started having a very slow acting aperture stop down lever, so now the exposures are off. It is a few years out of warranty so who is the best place to send it to to fix this as we have to pay for the service? We live in Virginia USA. Thanks for all replies!

David

[jatrax]

https://www.pentaxforums.com/forums/189-repairs-warranty-service/316284-penta...e-listing.html

[Adam]

Our DFA 100 Macro has started having a very slow acting aperture stop down lever, so now the exposures are off. It is a few years out of warranty so who is the best place to send it to to fix this as we have to pay for the service? We live in Virginia USA. Thanks for all replies!

David

I'd ask Eric if he has the necessary parts. That will probably be much more economical than sending it to precision.

[David&karen]

Thanks all! I took Adam's suggestion and emailed Eric and if he can do it I would really rather support the folks here. If he cannot I'll try Keh. Thanks again!

David

[BROO]

Is the sticky aperture on the 100mm DFA macro a known problem? There seems to be a lot of reports on this forum of this problem with this particular lens.

---------- Post added 06-05-16 at 04:12 PM ----------

I'm wondering because I have recently bought one.

[jatrax]

Is the sticky aperture on the 100mm DFA macro a known problem?

Define "known problem". There have been a number of reports of this, including mine. But whether that constitutes a "known problem" is well, "unknown". Is the issue more common with this lens than any other lens? Unknown. Is it as common as some other issues like SDM failure on da*16-50? Not even remotely close.

It's a fine lens and if it develops an issue, you get it fixed. We could do a poll and I'll bet the total number of issues with this lens is around 10, certainly less than 20. Out of 60,000 members and some unknown number who actually own the lens.

SMC Pentax-D FA 100mm F2.8 Macro WR Reviews - D FA Prime Lenses - Pentax Lens Reviews & Lens Database It gets a 9.60 rating in the review section, if it had a lot of problems I think that would be noted there and the ratings would be less.

[BROO]

"Known problem" for me is where there is a recognised design or manufacture defect resulting in a predictably high fail rate.
I'm hoping your right about the rarity of this issue, it's just I have read a number of times people asking about this issue with this particular lens. I think it is a fair question? I am very happy with this lens. I actually hope it becomes a template for future limited lenses.
Cheers

[Ex Finn.]

Is the sticky aperture on the 100mm DFA macro a known problem?

Got one here, slow as malassis!

[GodsPetMonkey]

Our DFA 100 Macro has started having a very slow acting aperture stop down lever, so now the exposures are off. It is a few years out of warranty so who is the best place to send it to to fix this as we have to pay for the service? We live in Virginia USA. Thanks for all replies!

David

Assuming you have the WR model (don't know if this is a problem with the previous version) it is a very easy fix. In fact, I just did it myself this weekend gone!

Basically the cause is some of the grease from the screw drive gears escaped and ended up under the aperture ring to which the lever is attached. Over time this has been moved around by the aperture ring and is now slowing down its free movement.

Fix is simple, unscrew the mount plate. Very carefully remove the mount plate - there are some tiny springs, most of which are attached attached to the electrical pins, but one is just freely there! Watch out, they will want to escape.

With the mount plate off you will see a matt blackish ring - that's the aperture ring. Carefully lift it and gently unhook the return spring on the underside. You should be able to see the problem now, a shiny greasy patch over near the screw drive, and the same on the underside of the aperture ring. Clean it up, I just used some isopropyl alcohol. Then just reassemble - reinsert the aperture ring, make sure you reattach the return spring before it is nestled, put the loose spring from the contacts in the one 'hole' that doesn't have a matching electrical pin in the mount, then affix the mount and screw it back on.

Your aperture lever should now be nice and snappy. Just like new! It took me about 15 minutes to do this, and a good chunk of that was spent hunting that damn loose spring!

If you like I can open my lens up again and take some pictures for you when I get home from work today.

[reeftool]

The lens likely has oil on the aperture blades and needs cleaning. Eric repaired my DA 40 Limited a couple of years ago for a similar problem. A "known problem" is heat like inside a hot car in the summer or too long in sunlight which can lighten lubricants and cause them to spread to areas they shouldn't be and that can happen to any lens.

[jatrax]

I think it is a fair question?

Absolutely! Did not mean to imply it was not. I was just having a bit of fun with "known problem" since that is a rather loose and undefinable statement. If a lens breaks once and it gets posted here then by definition that problem is 'known'. But is it a common problem? That I think is a different issue.

Slow aperture on the DFA 100 WR is a reported problem, mine had it and was repaired. I can think of at least 5 posts here with the same issue. But is it a design defect like the SDM drive, or just a normal percentage of any product that have an issue?

I suspect that as others noted above the cause of the failure is actually over heating. The metal design probably makes this worse by transmitting the heat better than plastic. So my guess is that this lens is somewhat more prone to heat caused movement of screwdrive grease onto the aperture blades. Defect? Not in my opinion, but YMMV.

[GodsPetMonkey]

If you like I can open my lens up again and take some pictures for you when I get home from work today.

Well, no one asked for it, but I am going to give it anyway. This really is a simple fix!

To start off, you need some equipment:
https://flic.kr/p/HtvsyU

* a bowl
* a pair of tweezers
* a screwdriver (size 0 or 00)
* grease cleaning fluid - I used isopropyl alcohol
* cotton bud

Remove the 5 screws on the baseplate. Make sure you use the right sized screwdriver or you will torque out and damage your screw heads.
https://flic.kr/p/HTZ8qi

Place the lens in the bowl and carefully remove the baseplate. There is a loose spring underneath you will want to catch and some of the electrical pins may not want to stay in their holder on the baseplate.
https://flic.kr/p/HKeMkQ

Find the tiny gold spring and put it safely in the bowl.
https://flic.kr/p/HtvKbS
https://flic.kr/p/HtvQyL
You don't want to lose it! The lens' chip and aperture contacts won't work without it.

Put any loose pins back into the baseplate then store it safely in the bowl.
https://flic.kr/p/GY9woN

Slowly lift the aperture control ring. There is a spring underneath that you need to unhook using the tweezers.
https://flic.kr/p/HMD3nK

That's all the taking apart you need to do. There should be some shiny grease under where the aperture ring sat - I had already cleaned mine before taking the pictures so I have 'painted' a drop of alcohol to show where it was.
https://flic.kr/p/Htw9G9

The grease seemed to have come out of the two holed metal disc on top of the screw drive mechanism. Poor diagnosed had the aperture ring floating over the top of that metal disc, and thus catching the grease.

Clean up the grease, it was pretty easy to remove, remember you don't want to damage anything here!

Be sure to clean any grease on the underside of the aperture ring as well!
https://flic.kr/p/HMDeDT

Putting the lens back together is the opposite of taking it apart. Start by putting the aperture ring back on. The long arm slots into a receiver that open the aperture blades, so make sure you put it in the right spot.
https://flic.kr/p/HMDiKP

Before you finish putting the aperture ring down, reattach the return spring with your tweezers. This is a bit fiddly, but is easier then the ring is being held just above the surface it sits on.

With the ring back in place, gently put the small gold spring back in its position.
https://flic.kr/p/HMDmzX

With the lens in the bowl you can carefully lower the baseplate back on. Make sure you watch the position of the pins to ensure they end up in the right place! None of my pins fell out when doing this, but if yours do the bowl or lens will catch them.

Once the plate is on, screw it down. Don't over tighten the screws. Once tha is done play with the aperture lever, it should be nice and snappy now. Job done. Test the lens of your camera to make sure it is recoding the correct aperture and lens information from the contacts.

If the aperture lever moves but doesn't snap back the return Spring probably unhooked itself, open it up and try again.
If the lens reports the wrong aperture or lens information one of the pins is out. Remove the baseplate, check the pins and carefully replace it.
If the lever is still sticky there is probably oil/grease on the blades themselves. A much bigger job.

[David&karen]

You know I have the right size screwdrivers, and they are the JIS kind that almost never slip unlike regular Phillips ones do. I'll try it this weekend, makes a good project!

David