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03-05-2017, 03:35 AM   #1
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Its always - Will not effect photo....

Hi Pentaxians,

I am currently on a lens buying binge (happens once or twice every year).

I am currently obsessed with Takumar M42's and grabbed many lenses with no plan to stop in sight. *Sigh* (i just cant stop - i need help )

So given the countless hours pouring over for sale section on a good many forums and scouring evil bay etc, I have come to realise that no matter what fault or issue a lens has, it NEVER affects the picture ability of the lens.

So what exactly DOES affect the picture taking ability of a lens?

I'd be interested in opinions on what should really be avoided at all costs.

At the mention of haze of mold/fungus, no matter how rare the lens or how much i have been looking for that exact lens i drop it off my list.

Can haze/mold/fungus be dealt with, without a costly CLA ?

03-05-2017, 04:02 AM   #2
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Moved to correct forum
03-05-2017, 04:13 AM   #3
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A scratch or blemish on the glass will have most effect if it is on the rear element near the centre. Can cause a smudge on the picture. Front element is less troublesome, but can lead to loss of contrast.

Haze will lead to loss of contrast and a soft image if it is bad. Fungus the same.

Haze is usually caused by balsam separation (the cement used to glue two elements in place and by its nature is usually difficult to deal with as you will need to separate two pieces of cemented glass. Fungus can be dealt with yourself by dismantling the lens and cleaning the glass in a vinegar solution. But some fungus can etch the coatings permanently, and sometimes the fungus can be between two elements that you cannot physically get to.
03-05-2017, 05:49 AM   #4
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Yeah, the rear element more easily causes problems. Scratched coatings can mean lower flare resistance, lower contrast, but its usually not a deal breaker. It doesnt cause visible defects, just overall lower image quality
Decentering is a more real problem. Or things like aperture blades being too oily, not closing correctly. And finally, with old lenses, there is a possibility that dust gets in. Dust is not a problem, unless it is some shiny material. Some dust spots are to be expected, though.
Element separation is bad, too.

03-05-2017, 05:51 AM - 3 Likes   #5
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"So what exactly DOES affect the picture taking ability of a lens?"

The photographer using it!
03-05-2017, 06:16 AM   #6
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I have a Super-Tak 50/1.4 and it has a 1cm scratch across the rear element... I've made hundreds of photos on film and digital with that lens and the scratch has NEVER made any sort of impact on image quality... the yellowing element on the other hand...



On the other hand, I have a 20mm prime with a scuffed front objective, and when shooting into contrasty scenes, or towards the light it does have a tendency to glow... but it still produces great images



Value is personal - you wont feel as though you got ripped off if your expectations are met.

Last edited by mattt; 03-05-2017 at 06:19 AM. Reason: added photos
03-05-2017, 08:53 AM   #7
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Most people wisely write "I have not seen any effect on image quality" which means they don't know what to look after and in what situations/images they should look. Most people don't write "it has no effect on image quality whatsoever".

Scratches on the front element, dust or fungus inside often lead to less contrast or ghosting/flares. These are most visible in bright scenes with some very contrasty black/dark in them. Dust may be most visible when using small apertures against very smooth backgrounds like clear blue sky.

03-05-2017, 10:28 AM   #8
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QuoteOriginally posted by NedKelly Quote
So what exactly DOES affect the picture taking ability of a lens?
You might find this interesting to read:

03-05-2017, 11:02 AM   #9
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Good information there - thank you all.

Ok so avoid Haze like the plague - got it.

Fungus CAN be a major problem and given i have no way to deal with, i should avoid that too - got it.

A small scratch on the front element is not TOO bad (using common sense to make a judgement)

A scratch on the rear element is more problematic - got it.

All good thing to know. Thank you again.
03-05-2017, 11:03 AM   #10
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QuoteOriginally posted by NedKelly Quote
Can haze/mold/fungus be dealt with, without a costly CLA ?
Removal = disassembly = CLA


Steve
03-05-2017, 11:09 AM - 1 Like   #11
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QuoteOriginally posted by NedKelly Quote
I'd be interested in opinions on what should really be avoided at all costs.
Personally, I avoid lenses that show evidence of being dropped or hit hard, such as the inability to accept filters.
This does not mean that lenses with these problems won't work properly. I still avoid them, because there is almost always
another one out there.
03-05-2017, 12:48 PM   #12
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QuoteOriginally posted by NedKelly Quote

Fungus CAN be a major problem and given i have no way to deal with, i should avoid that too - got it.
My advice.... buy yourself a cheap lens on ebay. Look on youtube or research on here how to dismantle it. Take it apart and clean it and put it together again. You will quickly get a feel for whether you like the challenge or not.
03-05-2017, 01:13 PM   #13
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QuoteOriginally posted by NedKelly Quote
i just cant stop - i need help
No, you need money.
03-05-2017, 08:36 PM   #14
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QuoteOriginally posted by bxf Quote
No, you need money.
lol: - yeah that helps.

Had a good night - picked up 6 Taks from various sellers. Still got my eye on a few more, plus 5 or 6 already inbound from the last few days/nights waiting for the last 15 seconds before i bid, on top of the 8 i received last week.

I want to get as complete a set of Taks as possible together - all the variants of each lens - or at least as many as i can find that are mint or very close to it.

I have seen some rare Taks pop up for sale but the scratched elements etc have been putting me off them.

Loving these Taks !



P.S: I suppose i should look at my credit card to see what I have spent this last 2 weeks - too scared ! Ah, to hell with it, you cant take it with you - right?
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