How do I quantify or see effect of dust in my lens?

6BQ5 · 09-03-2013, 12:42 PM

Ever since I got my K-30 in June I have been building up a small army of M42 primes in various focal lengths. Honestly, I love every single one of them and because of them I have only minimal LBA pangs.

Every single one of them has internal dust. The dust is very easy to see with the aide of a bright light. I have read in many places on the web that dust has a minimal impact, if any, on image quality. The worst it could do is affect the contrast in an otherwise beautiful and colorful photo. The dust has to be seriously huge for it to easily show up on a photo.

Is there some sort of extreme test condition that I could create where the dust on the inner elements of my lenses would actually show up in a picture and obviously stand out over any sensor noise? I'm just curious more than anything now.

Thanks!

bluenose · 09-03-2013, 12:58 PM

Not sure about any tests you can do but this article should remove any fear about internal dust in the lens. LensRentals.com - Front Element Scratches

Regards

JinDesu · 09-03-2013, 01:05 PM

For anything besides the rear element, I don't think it's entirely possible to see them. Besides maybe stopping down to F45 or something like that.

carrrlangas · 09-03-2013, 01:08 PM

Most probably, never! LensRentals.com - The Apocalypse of Lens Dust

Tanzer · 09-03-2013, 04:06 PM

Well, I'd have to think that at some point, dust can be a problem.

Like when a lens gets dusted from a color run. The Lens Rental guys say they won't cover that, so obviously that is "too much" dust.

I have some old hazy lenses, where you can see poor image contrast. I know a lens hood will help, but still, the fundamental problem is there .... so I think the question (how to objectively characterize the amount of dust) is a fair one. Don't know the answer though.

JinDesu · 09-03-2013, 04:57 PM

Originally posted by Tanzer

Well, I'd have to think that at some point, dust can be a problem.

Like when a lens gets dusted from a color run. The Lens Rental guys say they won't cover that, so obviously that is "too much" dust.

I have some old hazy lenses, where you can see poor image contrast. I know a lens hood will help, but still, the fundamental problem is there .... so I think the question (how to objectively characterize the amount of dust) is a fair one. Don't know the answer though.

I think the fear of the colour run dust is that the dust gets everywhere in excess - and can jam the focusing mechanism, for example. But normal dust on lens elements should be pretty invisible.

hoanpham · 09-04-2013, 03:32 AM

Try high-key photos, or directly light sources...
Dust that can lit up by a light source, in theory, can reduce the contrast.

f16 or f22 also visible, but depends.

nothing in my concern...

09-03-2013, 12:42 PM	#1
6BQ5 Veteran Member Join Date: Jun 2013 Location: Nevada, USA Photos: Albums Posts: 3,348	How do I quantify or see effect of dust in my lens? Ever since I got my K-30 in June I have been building up a small army of M42 primes in various focal lengths. Honestly, I love every single one of them and because of them I have only minimal LBA pangs. Every single one of them has internal dust. The dust is very easy to see with the aide of a bright light. I have read in many places on the web that dust has a minimal impact, if any, on image quality. The worst it could do is affect the contrast in an otherwise beautiful and colorful photo. The dust has to be seriously huge for it to easily show up on a photo. Is there some sort of extreme test condition that I could create where the dust on the inner elements of my lenses would actually show up in a picture and obviously stand out over any sensor noise? I'm just curious more than anything now. Thanks!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
How do I capture what I see?	6BQ5	Photographic Technique	16	07-22-2013 12:33 PM
Dust in Viewfinder, how do I get rid of it?	claimed4all	Pentax DSLR Discussion	12	04-07-2013 04:29 AM
I’d like to achieve macro of the magnification in this video. How can i do it?	dmbaile2	Pentax SLR Lens Discussion	14	05-16-2012 08:27 PM
how do i achieve this effect?	ajyp	Film SLRs and Compact Film Cameras	12	02-03-2012 01:44 AM
Question In Messages: how do I find my 'sent' mail?	Hilo	Site Suggestions and Help	4	01-16-2012 02:54 PM

09-03-2013, 12:58 PM	#2
bluenose Senior Member Join Date: Jan 2012 Location: S. Ontario Posts: 227	Not sure about any tests you can do but this article should remove any fear about internal dust in the lens. LensRentals.com - Front Element Scratches Regards

09-03-2013, 01:05 PM	#3
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	For anything besides the rear element, I don't think it's entirely possible to see them. Besides maybe stopping down to F45 or something like that.

09-03-2013, 01:08 PM	#4
carrrlangas Veteran Member Join Date: Mar 2012 Location: Joensuu (Finland) Photos: Gallery Posts: 1,761	Most probably, never! LensRentals.com - The Apocalypse of Lens Dust

09-03-2013, 04:06 PM	#5
Tanzer Veteran Member Join Date: Mar 2012 Location: Perrineville, NJ Posts: 1,375	Well, I'd have to think that at some point, dust can be a problem. Like when a lens gets dusted from a color run. The Lens Rental guys say they won't cover that, so obviously that is "too much" dust. I have some old hazy lenses, where you can see poor image contrast. I know a lens hood will help, but still, the fundamental problem is there .... so I think the question (how to objectively characterize the amount of dust) is a fair one. Don't know the answer though.

09-03-2013, 04:57 PM	#6
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	Originally posted by Tanzer Well, I'd have to think that at some point, dust can be a problem. Like when a lens gets dusted from a color run. The Lens Rental guys say they won't cover that, so obviously that is "too much" dust. I have some old hazy lenses, where you can see poor image contrast. I know a lens hood will help, but still, the fundamental problem is there .... so I think the question (how to objectively characterize the amount of dust) is a fair one. Don't know the answer though. I think the fear of the colour run dust is that the dust gets everywhere in excess - and can jam the focusing mechanism, for example. But normal dust on lens elements should be pretty invisible.

09-04-2013, 03:32 AM	#7
hoanpham Veteran Member Join Date: Nov 2009 Location: Strand Photos: Gallery \| Albums Posts: 1,366	Try high-key photos, or directly light sources... Dust that can lit up by a light source, in theory, can reduce the contrast. f16 or f22 also visible, but depends. nothing in my concern...