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Buying a lensWhat do you check for

G

Guest

Hi,

When buying a used lens, what are key things to search for, and what methods do you use? I know that fungus and haze are things to look for, but what is the most effective way to check?

Thanks

Daniel
 
G

Guest

Daniel,

The first thing to do is to, of course, get the seller to agree to "lend" you the lens for your own testing. This should be no longer than 7 to 10, days depending upon how long it takes to process the film and make prints. If this is not possible, then make sure you can return the lens for a full refund during a certain time period. Most reliable retail establishments have a 15 to 30 day return policy.

Scratched lenses can result in flare which of course reduces image quality. If you really have to have the lens, the fix may be to touch up the scratch with flat black paint using a very fine brush or marker.  Attempt this at your own risk and only if you have the hand of a brain surgeon. This is only necessary if the scratches are heavy and on the front element.  Small scratches, especially those on the back element of the lens, won't make much difference.  Scratches on the sides of the elements are also less likely to create a problem, especially when you stop down it may not even be in the light path.

Fogging or haze...The best way to check for fogging or haze in a lens is to shine a bright flashlight through one end of the lens and look through the other end of the lens.  The fogging/haze will show as a white colored cloudiness on the lens elements. Sharpness and contrast suffer from haze because of an increased tendency for the lens to flare. In most cases it can be cleaned professionally. Some cases are so severe because of deterioration of the lens coatings.  If this is the case, then the lens cannot be cleaned properly without removing the lens coating. This IMHO is not a good thing though there are those who might disagree.

Fungus problems occur alot in humid climates. Living near large bodies of water or having d& basements are the usual culprits  Fungus can actually etch glass. It sometimes can be cleaned if it is detected early. Looking through the lens you may see faint white lines/marks that either look like frozen lightening or jagged concentric circles. Then there is always the nose test. Take a wiff, if there's mold present you may smell it. This latter test was a prime way to tell if the camera had fungus damage inside.

Coating marks are often the same as cleaning marks. You see these by holding the lens surface perpendicular to your line of sight. The soft flourite coatings of Leica lenses are easily scratched by improper cleaning.  A small amount of lens cleaning marks or coating marks may make no perceptual difference in the performance of the lens. A large amount of cleaning marks or coating marks will make a small difference by possibly introducing a little flare.

BTW, if the lens is of great value, you probably know to get yourself a second or third opinion from someone whose judgement you trust. You'll never know what they'll find because they are not in a "must have or die" mind frame.

I hope this helps a bit.
Good luck in your search
 
G

Guest

Unfortunately for some of the older classic lenses it is necessary to buy second hand. There are also modern ones at considerably reduced prices available second hand.

In those circumstances I buy on condition the lens is sent to Solms for inspection at my expense and will be returned to the vendor if not acceptable. I have not found a seller who is not agreeable to this procedure.

TS@leica-camera.com can check a lens far better than we can, and find faults that are otherwise undetectable.

To cite but one ex&le I agreed to buy a second hand but apparently mint as new 1:4/35-70 Vario-Elmar-R from a dealer. At Solms it was found the lens elements were de-centred (sic). The cost of rectification was included in the equation and the dealer very decently reduced the price whereby we both went halves in the cost. I would not have otherwise bought the lens.

My advice - Send any second hand lens to Solms.
 
G

Guest

>To Justin Scott. What did Leica Solms charge you to examine the 35-70 4 Vario-Elmar-R? How long ago did you send it in? It was great that Leica determined an element was decentered. Many have said it is a hallmark of good lenses to be perfectly centered.
 
G

Guest

Thomas,

Leica Solms did not charge to examine the lens, but did charge when I elected to have it serviced.

I sent it to Solms in mid 2002.

Regards,

Justin
 

garth

Active Member
Hey all,
I'm currently looking at a lens that is significantly reduced because of a scratch on the rear element. I'd thought a scratch on the rear element was detrimental- but the above discussion states that scratches in the element are detrimental. Can anyone shed light on this?

I'm not sure how big the scratch is, it is through one of the reputable camera houses, and I've yet to inquire on that. It is a tele-elmarit, not sure if the first or second version either.

thanks,
garth liebhaber
 
D

dkhaw

Hello Garth
Not sure if this info will help - try this link:

Please, Log in or Register to view URLs content!


There is an article on scratched lenses. I reckon you should try and test the lens out by shooting a roll of film with it against the sun & at various light conditions.

Rgds
Daniel
 

garth

Active Member
Thank you very much, Daniel,
I just may be using the 90 i've long wanted. that was a very useful site.
ciao,
garth
 

kren2000

Active Member
No one can say for certain if a particular scratch will affect a particular lens optics. The only thing for sure is that it'll affect the resale value, which is often a good thing if you're a buyer. I'd prefer a lens with one deep scratch than one with lots of small cleaning scratches.

The best thing to do is to ask for a test-roll and return privileges. Take shots in flare situations, but know that you might just have a flare prone lens even if it was mint!

Karen
 
M

martoski

Hello to everyone.
Does someone has any information, clear, abaut ussing 12 mm or 15mm voigtlander on m7 ? i have been reading but is not clear, aswell i sow it in a m6.

thanks
 
D

dkhaw

Hello Members
I was chatting with a pro last week and he told me some horror stories of his Canon lenses fogging up.

Can anyone let us have an idea how a lens could "fog-up"? Is this caused by the repeat in & outs of the lens from a very cold to warm temperature such as air-conditioned indoors out into the hot, humid outdoors? How do we prevent this phenomena from happening on our lenses?

Thanks & kind rgds
Daniel
 

0000

Member
Daniel,

You must allow GRADUAL acclimatization. Let your gear warm or cool down SLOWLY.

You do this by putting the gear in a zip lock freezer bag.

Squeeze out most of the air. Not all of it.

Then go out into the warm humidity. After 30 minutes.

The gear should be equalized. Take it out. Shoot.

Seperate bags for bodies and lenses for larger than M stuff.

It works because you gradual take the air you trapped in the bag

from the one enviroment and warm it up SLOWLY.

The reverse is needed if you go from extreme cold to warm

As was the case during my time in Moscow inthe winter.

Simply bag the gear after being outside for a long time and let is warm up inside for a while and them take it out.

Just Bag it!
 
D

dkhaw

Thanks David - I thought this thread was long forgotten! I do use a similar method as yours and it does work.

What I meant about fogging of the lens is a permanent fog-like coating inside the lens which damages the lens forever. My theory is this: Is it caused by the condensation of moisture inside the barrel through transferring the lens in & out of different ambient temperatures too often allowing condensation of moisture to take place? The condensation could be acidic, etc caused by air pollution and it attacks the lens surface leaving behind a permanent coat.

Daniel
 

wang

Well-Known Member
Another possibility is the debris left behind by the opening and closing action of the aperture blades.
 
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