The dreaded "flashlight" lens test

My straight out of the box new (old stock) Nikkor 50 f1.4 does not pass the flash light test even it being new. The lenses are not sealed inside, dust and particles can go in. Sometimes more than that....

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p.giannakis said:
My straight out of the box new (old stock) Nikkor 50 f1.4 does not pass the flash light test even it being new. The lenses are not sealed inside, dust and particles can go in. Sometimes more than that....
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Sure, a little dust can get in. But the lens you pictured, I would say, goes a bug too far! By the way, did you mean to say it was a Nikkor? It seems to be a Minolta.
 
Out to Lunch said:
I've never even heard of this 'test'. Who uses it and for what purpose? Cheers, OtL
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LED flashlight, i.e., a point source, will reveal lens flaws like fungus, scratches, haze, separation, that a non-point (’extended’) source will not. Viewed with extended light a lens can appear flawless.

https://www.kenrockwell.com/tech/flashlight-test.htm

This is an excellent explanation of why it can be valuable, and when, and why it may not be. :)
 
Phil_F_NM said:
This is the photography gearhead version of body dysmorphic disorder.
Perhaps, lens dysmorphic disorder; then again, this would also be applicable to other gear as well, but the lenses are the pieces most obsessed over in this way.

Phil Forrest
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This is it, exactly.
 
The flashlight test feeds the anxiety inherent in all Leica user's DNA, more so the new members of the club who thinks that the lofty price-tag equals perfection.
Other than truthful description and illustration, I don't see what else can be done, unless you can find a way to sell in person locally.
 
I have seen examples of lenses that looked very bad with a flashlight, yet the photos they made were fine.
 
Yes, indeed, lenses can still perform without any effect, even with many internal ‘defects.’

The flashlight test is useful to reveal haze that otherwise won’t be seen by the naked eye but can lower contrast. Takes a lot of fungus to affect images, but fungus always affects the price. :)

Scratches rarely cause issues.

How about cracks? https://www.lensrentals.com/blog/2008/10/front-element-scratches/
 
I worked in astronomy sales and my boss used to go mental when people complained that they had stuck a flashlight into the telescope objective and there was dust and 'who knows what else'. He would ask them if it showed up on their images (we sold a lot of imaging scopes) and they would always say no but now they know it is there.....!

They got short shrift from him!
 
kkdanamatt said:
What is the best way to advertise and explain that the flashlight test is not always an accurate measure of how the lens will perform?
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As I see it, it's not up to you to explain such things. By all means be honest and provide accurate, detailed information - photos and descriptions of flaws, and example photos showing the good and the bad - but leave it at that. Encourage those who want more information to contact you directly. Most buyers won't bother.

kkdanamatt said:
I don't want to sell the lens and then have the buyer ask for a return.
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And that is where providing a solid description comes in. It's your protection against returns. A buyer can return an item from an "as-is, no returns" listing if they can prove to the 'bay that the item didn't match the description. When listing an item as "no-returns" the site makes sure you are aware of that policy.
 
It's tricky, because you never know what kind of buyer you're going to get. I do think raking yourself over the coals in a listing with pictures of a "flashlight test" is poor salesmanship, and kind of self-defeating. It's quite common to see descriptions with "light dust, does not affect picture quality" or similar, and of course the actual degree varies wildly depending on the ethics of the seller. But if it were me, I'd probably state something like that and then include a lot of photos, and direct the potential buyer to judge image quality by those. If you stress-test the lens for flare, fog or similar by shooting into light and maybe showing some crops, I feel like that is an honest (and actually unusually thorough) way to demonstrate the condition of the lens. That seems more realistic due diligence than posting a photo of the optics in their worst possible representation i.e. a flashlight pic.
 
I have a ten-bladed coated Summitar with some kind of strange growth inside that I could never sell as jewelry but which makes stunning color images. It's strange, the lens market.
 
As many others have said, honest and detailed descriptions are the best counter for this. "Ratings" are subjective, and the ones used on eBay are famous for being bogus. I've seen "Mint" used to describe badly damaged lenses with lots of fungus simply because the outer lens barrel is relatively clean. You have more of a leg to stand on if you put in plain terms exactly what you see and what it means.



Of course nothing will protect you if a buyer is a scammer or a fool.
 
agentlossing said:
It's tricky, because you never know what kind of buyer you're going to get. I do think raking yourself over the coals in a listing with pictures of a "flashlight test" is poor salesmanship, and kind of self-defeating. It's quite common to see descriptions with "light dust, does not affect picture quality" or similar, and of course the actual degree varies wildly depending on the ethics of the seller. But if it were me, I'd probably state something like that and then include a lot of photos, and direct the potential buyer to judge image quality by those. If you stress-test the lens for flare, fog or similar by shooting into light and maybe showing some crops, I feel like that is an honest (and actually unusually thorough) way to demonstrate the condition of the lens. That seems more realistic due diligence than posting a photo of the optics in their worst possible representation i.e. a flashlight pic.
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By comparison with most sellers, you're right, what the OP is doing seems excessive. However the people who have tried to sell me lenses with severe haze could have saved me and themselves a lot of trouble, had they done a flashlight test. Including pictures of it I also wouldn't recommend, it's hard to take them, and few would be able to interpret them.
 
Flashlight test cuts both ways. I’ve bought lenses off eBay sellers who knew nothing about lenses and asked them to do the test, it’s helped me negotiate a few bargains.

Knowledgeable Leica buyers know how common faint haze can be, they will pay more for a spotless lens but won’t be expecting perfection if the words in the sales description are chosen carefully (so as not to unnecessarily devalue) and accurately so as to describe the true condition.
 
The flashlight lens test is usually one of two things.

One, a perfectionist obsession with neurotic photographers looking for the ideal (= perfect) lens. Which doesn't exist. Everything has dust on or in it.

Two, a scam occasionally pulled on unwary sellers by Ebay buyers who want to get the price of a lens dropped to as low as possible. I've had buyers try this trick on me a few times. My response was to cancel the sale, block the buyer and relist the lens.

In your lens details, don't overdescribe, but be very clear and also be sure to state your sale conditions. Mine are "sold as is, no returns". I strongly recommend to avoid mentioning the flashlight test in your text - it's largely irrelevant anyway, and why put the idea in dishonest buyers' minds in the first place?

As for price, check completed Ebay sales and read the sellers' descriptions. Many tend to overprice their goodies but in the end the buyers often as not pay what an item is worth. Or it gets passed in.

Take it from one who knows...
 
If it's a lens that typically sells for more than $1500 or so but shows a bit of haze, I find it worthwhile to spend the $125+- to have Youxin Ye CLA it. You'll get your money back and more for selling a clean lens.

I will buy lenses at a significant discount if there is haze that I have a good idea that a CLA will clean it right up.
 
84Bravo said:
If it's a lens that typically sells for more than $1500 or so but shows a bit of haze, I find it worthwhile to spend the $125+- to have Youxin Ye CLA it. You'll get your money back and more for selling a clean lens.

I will buy lenses at a significant discount if there is haze that I have a good idea that a CLA will clean it right up.
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Of course, a $1500 lens should have a CLA if necessary.
As I said in my first post, I'm concerned about a regular 90mm Elmar, for example, that should sell for about $200-$250 in clean condition.
 
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