The flash light test...

BradS · Jul 24, 2019

I made the mistake of submitting a few of my "known good" lenses to the flash light test last night. I don't know what came over me. These are lenses that have consistently produced good results for me. Glass that is clean....except for the usual internal dust.

Oh, The Horror!

What compelled me to this tragic error, I cannot say.

Save yourself!

Keep that dammed flashlight away from the optics with which you are well pleased.

Sirius Glass · Jul 24, 2019

The next time you get an urge like that there are three options:

Walk away and take a strong drink.
Go on the internet and shop for yet another lens.
Both of the above.

Kino · Jul 24, 2019

Once seen, can't be unseen...

Just don't look!

chip j · Jul 24, 2019

ALL my many lenses PASS!.

Helios 1984 · Jul 24, 2019

The Topcor 4.4cm on my Topcon rangefinder would give nightmares to grain peepers. When you shine a light, it’s as if the Devil had pressed his thumb against the front glass. It produces sharp pictures nonetheless..

Chan Tran · Jul 24, 2019

BradS said:
I made the mistake of submitting a few of my "known good" lenses to the flash light test last night. I don't know what came over me. These are lenses that have consistently produced good results for me. Glass that is clean....except for the usual internal dust.

Why I did this, I cannot say. I feel as if some demon possessed my being for a few minutes and compelled me to this tragic error.

Save yourself!

Keep that dammed flashlight away from the optics with which you are well pleased.

I am lost! What is the flash light test?

bdial · Jul 24, 2019

Chan Tran said:
I am lost! What is the flash light test?

Don't ask, lest you be tempted to do it.
You shine a small flashlight through the lens to look for haze, internal dust, fungus or whatever. It highlights whatever flaws are there better than just looking through it without the light.

Most lenses will show up something, most somethings you might see don't have any real effect, especially various specs of dust, or small bubbles or similar imperfections in the glass. But it all looks scary. It's a good way to bargain down the on the price of a lens you might be buying.

Theo Sulphate · Jul 24, 2019

Flash light test is good way to give yourself a heart attack. Don't do it!!!

In my house, the flashlight is at maximum possible distance from the Camera Room.

Have considered keeping the flashlight outside!

BrianShaw · Jul 24, 2019

I’ll never forget the first time I did that... scarred me for life. I’ve never touched a shutter speed tester because I know I couldn’t handle that!

Luckless · Jul 24, 2019

Maybe I'm just weird, but I enjoy seeing all the 'weirdness' and anomalies that can show up in a lens while still projecting a decent image.

However I'm also geeky enough to enjoy signal processing and such. [I like telescopes and such for astronomy, but I'm the kind of person who doesn't actually care all that much about what's up there or what's going on that far out, I just enjoy finding ways to get a better image of it...]

Ariston · Jul 24, 2019

My lenses aren't pretty, but they pass the flashlight test much better than I pass the mirror test.

Chan Tran · Jul 24, 2019

bdial said:
Don't ask, lest you be tempted to do it.
You shine a small flashlight through the lens to look for haze, internal dust, fungus or whatever. It highlights whatever flaws are there better than just looking through it without the light.

Most lenses will show up something, most somethings you might see don't have any real effect, especially various specs of dust, or small bubbles or similar imperfections in the glass. But it all looks scary. It's a good way to bargain down the on the price of a lens you might be buying.

Oh that I do it all the time. Doesn't do anything to the lens or to me.

Chan Tran · Jul 24, 2019

BrianShaw said:
I’ll never forget the first time I did that... scarred me for life. I’ve never touched a shutter speed tester because I know I couldn’t handle that!

I test the shutter often. Doesn't hurt anything.

Sirius Glass · Jul 24, 2019

I fire all my shutter every three months. It is on my schedule.

Huss · Jul 24, 2019

I bought a Voigtlander 50 3.5 from B&H. The flash light test showed a freakin bug in the lens! As in an insect. Sent that lens back..
Thank u flash light test!

Helios 1984 · Jul 24, 2019

BrianShaw said:
I’ll never forget the first time I did that... scarred me for life. I’ve never touched a shutter speed tester because I know I couldn’t handle that!

Within tolerances, within tolerances, within tolerances *cross fingers lolll

chip j · Jul 24, 2019

For flashlight test use a black background.

RalphLambrecht · Jul 24, 2019

BradS said:
I made the mistake of submitting a few of my "known good" lenses to the flash light test last night. I don't know what came over me. These are lenses that have consistently produced good results for me. Glass that is clean....except for the usual internal dust.

Oh, The Horror!

What compelled me to this tragic error, I cannot say.

Save yourself!

Keep that dammed flashlight away from the optics with which you are well pleased.

don't fix or test what ain;t broken.

KN4SMF · Jul 24, 2019

I always used a 60W bulb for the purpose, but I suppose it doesn't matter. But if a lens can't pass the test, and my standards are indeed very strict, the lens doesn't go on my camera. i either open it up for cleaning, or scrap it if there are scratches or etching.

Helios 1984 · Jul 24, 2019

KN4SMF said:
I always used a 60W bulb for the purpose, but I suppose it doesn't matter. But if a lens can't pass the test, and my standards are indeed very strict, the lens doesn't go on my camera. i either open it up for cleaning, or scrap it if there are scratches or etching.

Next time, please, drop it in our freebies section. Whatever the lens, I'm sure someone need screws, aperture blades or a rear element.

jim10219 · Jul 24, 2019

I have an old Petzval with a big chip near the center of the rear element. The photos it takes look great.

Since experiencing that, dust doesn't bother me.

StepheKoontz · Jul 24, 2019

I could care less about dust. Fog and haze on the other hand destroys contrast.

mcfitz · Jul 25, 2019

Easy remedy, switch to pinhole photography.

Huss · Jul 28, 2019

The bug that B&H sold me for $400, but they threw in the lens for free:

Arklatexian · Jul 28, 2019

jim10219 said:
I have an old Petzval with a big chip near the center of the rear element. The photos it takes look great.

Since experiencing that, dust doesn't bother me.

"Pops" Whitesell, who had a studio in the "French Quarter" of New Orleans, preferred allowing spider-webs to exist inside his lenses to a clean, razor-sharp lens. Used a Packard shutter also. I think he became a Fellow of the Photographic Society of America for his work, even after F64 was organized in California. Later, after losing a leg to diabetes, he still made pictures as well as traveled, lectureng to professionals and advanced amateurs. Could it be that too much weight is being given to the value of "ultra-sharp" lenses in the making of "creative" photographs? I wonder. I have even heard of Hasselblad/Zeiss lenses criticized as being to "too sharp". Mine are NOT for sale......Regards!

The flash light test...

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