slow diaphragm?
I have an M 28/2.8 (yes, I know, spare me the "but the 3.5 is much better" comments, I've heard it already) that I picked up used a while ago. Lately, I've been getting really overexposed shots when I use f16 or 22. The slides look up to 3 stops overexposed, and I'm not having the problem with any other lens. I suspect that the aperture is a little slow and it just isn't stopping down fast enough, therefore letting in too much light. Does this explanation make sense? I'm just looking for a little confirmation before I run out and buy another 28 (and yes, this time I'll try to get the 3.5). In slightly OT news, I had a hour and a half seminar on endoscopy this morning, no Pentax content however ;-) -Matt
Re: How much does it cost to fix a slow diaphragm?
Anton Browne e-mailed me off list with what seems like a very good suggestion: I had that problem once on a Pentax lens - the lens was tatty but optically fine and I'd got it cheap, it was a common lens so I wasn't too bothered. I set the lens to close focus so it was extended and carefully lubricated the mechanism that can be seen inside that operates the diaphragm (I did this with watch oil or WD40 can't remember which on a wooden toothpick so I could be very accurate and apply tiny amounts). Hey presto lens fixed. _ Chat with friends online, try MSN Messenger: http://messenger.msn.com - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: How much does it cost to fix a slow diaphragm?
On 4 Aug 2002 at 0:34, Peter Spiro wrote: > I was offered a 50mm A f/1.4 lens in mint condition, but I noticed that the > diaphragm closes slowly. It does not have any oil visible on it, which is the > usual cause of slow diaphragms, so I'm concerned that a simple cleaning won't > fix it, and it may have a more costly mechanical problem. Does anybody have any > experience with this? Peter, It could require a very simple repair, I have bought lenses with similar symptoms. All were fixed by removing the mount then cleaning and re-lubricating the aperture coupling rings which rotate at the rear of the lens and couple to the actual aperture mechanism. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
How much does it cost to fix a slow diaphragm?
I was offered a 50mm A f/1.4 lens in mint condition, but I noticed that the diaphragm closes slowly. It does not have any oil visible on it, which is the usual cause of slow diaphragms, so I'm concerned that a simple cleaning won't fix it, and it may have a more costly mechanical problem. Does anybody have any experience with this? _ MSN Photos is the easiest way to share and print your photos: http://photos.msn.com/support/worldwide.aspx - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
