f8lee Loc: New Mexico

You know, the entire "use a filter!" - "filters are not needed!!" nonsense aside, I ended up accidentally discovering just how crucial (or not) some kind of obstruction in front of a long lens is (or is not - you decide).

In October 2020 I was out attempting to capture the moon rising over the Organ Mountains in Las Cruces NM, with the Fuji 200MM f2.8 lens plus 2X TC. While waiting for the moon to appear, I was joking around with a little T-Rex toy i carry as a kind of "Flat Stanley" (look that up if you don't know the term), and so snapped a shot of the toy standing inside the lens hood (you know, because he was 'helping' me!)

So after waiting and waiting, the moon finally popped up and I took some shots. I also took a shot with my phone in order to be able to capture GPS coordinates that I could apply in Lightroom. And then I started breaking down the gear - imagine my shock when I discovered I inadvertently left T-Rex exactly where you see him in the second image below! I just figured the night was ruined and was pretty ticked off at myself, but when I loaded the images into LR I really could not tell there was any obstruction at all.

Of course, my having been shooting at F4 (2.8 lens plus 2X TC) and focusing at infinity no doubt partially explains this, but still I was quite surprised that there is effectively no distortion caused by that rather large "dust speck" or "scratch" directly on the front element of the lens.

The point being, it may not make as much of a difference as one might think, depending on circumstances.

So here is the setup - I tok this shot when I was finished in order to have GPS cooriantes to apply to the image


Here is T-Rex standing in the lens hood - taken before the mon rose (as you can tell from the light sky)


And this is the actual shot - I did not find any sign of T-Rex's having been sitting 1" in front of the front element

Jimmy T Loc: Virginia

Here is a One-Trick Pony on the subject: http://kurtmunger.com/dirty_lens_articleid35.html
I think that we just had a multipage discussion on the filter vs. no filter.
I'm sorry for your loss. . . .
Best Wishes,
JimmyT Sends

elee950021 Loc: New York, NY

Great image, regardless!

Be well! Ed

f8lee Loc: New Mexico

Thank you very much - but the point is that the rather large obstruction right in front of the lens seemed to have no impact - so a slight scratch would logically be less likely to create problems.

User ID

Thaz very real if the scratch occurred under your watch. But if you bought it dirt cheap with a harmless cosmetic defect, well halleluloo for you !

Unless its a Leica. Then you must bury the lens and then kill yourself.

bwana Loc: Bergen, Alberta, Canada

It is quite amazing how badly a front element can be damaged and still perform very well. The biggest problem I've run into is a (sun) flare from a scratch when a bright light directly hits the lens. Other than that, I wouldn't worry too much a few minor scratches.

bwa

therwol Loc: USA

I wouldn't give you two cents for a lens with a scratched rear element. If you go to this web site and scroll down where it says Lens Rear Element Scratch test, you will find pictures of the actual effect this can have on pictures, worse at small f/stops. You get dark, shadow like defects in the pictures.

https://onfilmonly.com/damaged-lens-rear-element-scratch-test/

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The front is the typical victim, but when its the rear its usually The End.

OK, I confess to punning ... but its true. The rear is the killer.

For front scratches, long FLs are nearly immune to any effect. OTOH for ultra wides anything worse than the slightest scratch to the front is usually visible in the sky or other less detailed areas. Stopping down makes it much worse.

This little gem (non-fisheye) can image a fruit fly resting on the front glass.

(Download)

Likewise.

(Download)

kpsk_sony

If you can see it in your pictures ... too bad.

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Hate random fruit flies in my skies :-(

ORpilot Loc: Prineville, Or

I have a RX10m4 it has a 2mm scratch on it at about the 10 o-clock position about 1/4 of the way in. At wide angle stops it doesn’t show at all unless the sun is directly on the scratch. It does show up at all zooms if I am shooting at f11 or higher. 90% of the time I can remove it in PP.

User ID

If you can throw $$ at it, a shop could loosen the front ring and rotate the glass so the scratch gets moved to "12 oclock". That section is not imaged by a 2:3 or 3:4 format. And then acoarst get a filter on there for next time.

imagemeister Loc: mid east Florida

THAT is the $64 question .......I have lenses that looked BAD - I mean scratches/chips you could FEEL with your finger nail - front OR back - and performed very WELL - unbelievably well !

ORpilot Loc: Prineville, Or

One of my students gave me the camera to “test it out” . It had the scratch when he got it. I tested and returned it to him photos of the images with the scratch flair. He kept it for a few months. He purchased a new RX10m4 and sent me the scratched camera as a gift. I was thrilled with the gift. I just work around the flair. Thanks for your “fix” idea. I’ll wait for the RX10m5 if it ever comes out.

Arrow points at scratch

Scruples Loc: Brooklyn, New York

One of the ways to see if an image is affected by a scratch is using a constant light source such as a LED light with a color filter on it. You can also use a video LED light. Looking at the light head on rarely shows a degraded image. Move the light around as in up, down and side to side. If the scratch is affecting the image you could repair it (for a lot of money for not very much) You may also use it for a paperweight and buy a new one!!