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Post by John Farrell on Sept 15, 2023 0:28:48 GMT
A vandal with more enthusiasm than sense has tried to open the back of this lens - a Pentax SMC 200mm f4. The result is a deep scratch on the rear element. Apart from the scratch the lens is in nice condition, so I'm going to try an old trick - filling the scratch with black paint.  |
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Post by nimbus on Sept 15, 2023 12:06:40 GMT
Presumably a case of "how hard can it be" from the person trying to get into it.
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Post by gray1720 on Sept 15, 2023 16:29:56 GMT
Presumably a case of "how hard can it be" from the person trying to get into it. I resemble that! I have a battered Kodak 620 folder that actually has a *chip* in the rear element. How the duck did that happen? |
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Post by steveandthedogs on Sept 15, 2023 16:48:56 GMT
You dropped it in the fryer?
S
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Post by gray1720 on Sept 15, 2023 19:44:19 GMT
You dropped it in the fryer? S Groan! |
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Post by nickr on Sept 16, 2023 5:04:30 GMT
Worth a go - although rear element scratches are worse than front element ones, with a tele lens, you might get away with it.
Never shot with one of these, and do rather fancy them - I'm a bit of a sucker for a compact 200mm. I've got the slightly odd 150mm f3.5, mostly because it's a slightly odd focal length. Less contrast than my other Pentax primes, but very sharp - part of its oddness.
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Post by John Farrell on Sept 16, 2023 6:25:47 GMT
Worth a go - although rear element scratches are worse than front element ones, with a tele lens, you might get away with it. Never shot with one of these, and do rather fancy them - I'm a bit of a sucker for a compact 200mm. I've got the slightly odd 150mm f3.5, mostly because it's a slightly odd focal length. Less contrast than my other Pentax primes, but very sharp - part of its oddness. There's no sign of the scratch, looking through the viewfinder of a K1000. I haven't done the paint thing yet - I'll get some artists acrylic and a fine brush first. |
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Post by aitch on Sept 16, 2023 8:15:35 GMT
Isn't there some optical equivalent of the stuff Autoglass (other windscreen fixing companies are available) use for filling in cracks and chips in windscreens? Or are there too many different types of optical glass for that to be viable?
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Post by andy on Sept 16, 2023 9:00:17 GMT
Worth a go - although rear element scratches are worse than front element ones, with a tele lens, you might get away with it. Never shot with one of these, and do rather fancy them - I'm a bit of a sucker for a compact 200mm. I've got the slightly odd 150mm f3.5, mostly because it's a slightly odd focal length. Less contrast than my other Pentax primes, but very sharp - part of its oddness. There's no sign of the scratch, looking through the viewfinder of a K1000. I haven't done the paint thing yet - I'll get some artists acrylic and a fine brush first. Never had to do such a repair but I think I'd rather use model paint like the Tamiya stuff. They are designed for thin coats and detailed work. Consistency between tubs of it is probably less important here though...or suitability for airbrushes. |
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Post by nickr on Sept 16, 2023 9:09:50 GMT
Worth a go - although rear element scratches are worse than front element ones, with a tele lens, you might get away with it. Never shot with one of these, and do rather fancy them - I'm a bit of a sucker for a compact 200mm. I've got the slightly odd 150mm f3.5, mostly because it's a slightly odd focal length. Less contrast than my other Pentax primes, but very sharp - part of its oddness. There's no sign of the scratch, looking through the viewfinder of a K1000. I haven't done the paint thing yet - I'll get some artists acrylic and a fine brush first. I would try a black marker pen first as proof of concept - probably easier to remove if it makes things worse. |
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Post by nickr on Sept 16, 2023 9:13:27 GMT
Isn't there some optical equivalent of the stuff Autoglass (other windscreen fixing companies are available) use for filling in cracks and chips in windscreens? Or are there too many different types of optical glass for that to be viable? Yeah, if it's not the same refractive index as the lens element, it will make things worse. So long as the scratch isn't massive, stopping it's impact, rather than fixing it, will do fine. |
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Post by John Farrell on Sept 16, 2023 19:45:59 GMT
There's no sign of the scratch, looking through the viewfinder of a K1000. I haven't done the paint thing yet - I'll get some artists acrylic and a fine brush first. I would try a black marker pen first as proof of concept - probably easier to remove if it makes things worse. I don't have a pen with a fine enough tip...and I do have Humbrol black hobby paint, but I haven't opened it in years. |
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