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New (old) lens

Posted: Mon Oct 22, 2007 3:34 pm
by eccles
As a relatively new Sony Alpha user I've been watching out for ebay bargains to build up my kit. Early Minolta lenses fit the Sony and are of very high quality. Last week I picked up an old Minolta 7000 film camera and two lenses, one of which was a 70-210 F4 known as the beercan. It's called that because it's about the same size as a 500ml can and is made of metal. It's very rugged, and that's just as well as the seller should have been shot for non-disclosure. It had had a hard life! There were several micro-scratches on the front element, the barrel was scuffed and the aperture leaves were sticky. Also the camera had a crack in the prism housing and the viewfinder shutter and aperture display wasn't working. If I'd complained though I'd have been obliged to send it back, and I wasn't going to do that. Not on your life! I stripped the beercan down and freed up the aperture leaves, and now, despite the scratched front element it takes super photos.
Here's a shot I took with it a few days ago. There's no extension tubes or attachments, just the beercan and my camera:
Image

But look at the detail from this 100% crop of the same photo:
Image

This was taken from about a meter away, so with a Canon 500D close up lens attached this is most likely going to be my butterfly lens of choice next year.

The cost was £77 for the lot including postage. The camera is back for sale and I doubt if I shall get much for it, a fiver if I'm lucky. But the other lens is a 50mm prime in good order and there's a fair old market for those and I should get around £40-50 for it. AND there was a half tidy camera bag as well. :)

Posted: Mon Oct 22, 2007 4:33 pm
by Chris
Good work... it sounds like an unusually successful episode of "Bargain Hunt"... I'd go check out your attic while you're on a roll...

Posted: Tue Oct 23, 2007 7:56 am
by Dave Mac
Its surprising how much abuse the front of the object glass of a lens can take particularly one with a long focal length. If for example you painted a large black cross on the front of the lens and took a picture the chances are that you would not see it in the picture (it simply reduces the amount of light getting to the camera). It follows that most dust spots don't show, you might do more harm to the lens cleaning the dust from the object glass than leaving it in place. The exception to this are scratches which have the effect of scattering the light and causing flare.
However any dust on the rear element will usually show on the pictures and should be delicatly cleaned off with a lens brush
Dave

Posted: Tue Oct 23, 2007 2:56 pm
by eccles
The exception to this are scratches which have the effect of scattering the light and causing flare.
Good point. I shall have to try a few shots against the light to see how it handles flare. The lens didn't come with a hood either, but I have one from another lens that fits so I'll make sure that I use it.

Posted: Tue Oct 23, 2007 4:00 pm
by Dave Mac
I don't remember where I read this but if you have a deep(ish) scratch on an object glass it it better to fill it in with black paint rather than leave it untreated. The black mark on the surface will not show on your pics and it will cure any lens flare.
BTW Eccles I forgot to mention what a super photograph you took with your new (old) lens
Dave

Posted: Wed Oct 24, 2007 4:07 pm
by eccles
These aren't deep scratches; they're tiny, barely scraping the multicoating and you have to catch them in a certain light to see them. Maybe the result of clumsy cleaning as some of these old multicoatings can be quite soft. It's difficult to ascertain what effect the scratches have, possibly a little loss in contrast maybe but I've still to test the lens against the light. Thanks for the compliment on the pic. :)

Posted: Sat Oct 27, 2007 6:59 pm
by LCPete
Hi Eccles really nice shots well done finding the bargains
Pete

Posted: Sat Oct 27, 2007 11:49 pm
by eccles
Hi Pete, glad you found your way from POTN. Thanks for the kind words.

Posted: Sun Oct 28, 2007 8:49 pm
by LCPete
Thanks Eccles Ive only just found this forum. Im making plans for next years butterflies already!
Pete