55LS: mis-sold or nothing to worry about?

[soylent]

Hi all,

Looonng time lurker, first time poster, and a bit apologetic the first post is a whinge.

I bought a used 55LS off of the For Sale section from a fellow LuLa member a few days back.

It's in good working order, but there's what I think is a *lot* of dust and black flakes lining the rear element and inside of the front element. I've got a four other LS lenses ranging up to three years old, and none show this amount of dust or flaking.

Links to dropbox in case the attachments don't upload:
white wall and ambient light, not a flashlight -- https://www.dropbox.com/s/nlldwtcmdb1ldf7/55LS%20spots.jpg
clean sensor and LR spot visualisation -- https://www.dropbox.com/s/a2cc0q37bkmljxw/spot%20removal%2055LS.png

I shoot a fair bit against colour backdrops and open skies, so I'm not looking forward to the spot removals or few hundred spent on a lens CLA

Seller's answer was (paraphrased) "I did a quick check, determined dust was normal and not worth mentioning. Every lens has dust. no refunds, sorry"

So was hoping for some input - what do you think?
  - youre being nit-picky, the dust isn't a big deal
  - buyer beware, eat the service cost from PhaseOne in Denmark
  - send it back for a refund


Thanks!

[Paul2660]

Was it listed as "mint" or "excellent condition"?  if so, I would question that.   I don't own the LS stuff, so can't speak to quality, but they list for 3.5K or so, and I don't think flaking would be OK. 

If the lens was listed as used some wear etc. then you are in a tough situation especially if optically all is OK.  It sounds like the inside coating has come off, as that is all I can think of "black flakes" and this might get worse over time. 

Paul

[pixjohn]

Thats a big issue to not post! I hope you paid with a credit card or paypal if the item was listed in good shape. What did the ad say?

P.S. I would also post the original ad here.

[Ken R]

Humm, It has been my experience that dust inside a lens does not show up as dust spots in an image. If you see spots in your images it is dust on the sensor not the lens. Dust and particles inside the lens might degrade its optical quality if the quantity and size of the dust is extreme otherwise it is more of an annoyance that only really matters when you look at the lens.

That said. Used Lenses with a lot of dust inside are usually sold a bit lower in price than the average price for a similar lens. The condition is most times disclosed in full prior to the sale.

[Chris Livsey]

Should you not dust map another lens then subtract the difference to eliminate sensor contamination?
Optically I can't see the lens dust, and I don't say you haven't a good point with the seller, looking like that. Too sharply defined IMHO.

[soylent]

Thanks for the quick replies, everyone!

I agree that dust doesn't normally appear in an image and it's never bothered me on any other lens I've got; it was the sheer quantity of it that surprised me (plus the seller's dismissive attitude).

The sensor's clean so all of the spots are from the lens.

I've gotten a quote for £156 from my dealer to send it back for a service and clean from PhaseOne in Denmark, so considering that I paid a bit under market value I think I'll put aside emotion, keep it and hope that a service doesn't turn up any other issues.

As a complete aside, I've only ever seen two cases where even a scratch on an element was visible in the final image:

• an old meyer trioplan that's known for its 'soap bubble' bokeh on specular highlights: dust and scratches on the front element showed up as repeating patterns in the bokeh
• oil spots or scratches on the rear element showed up as spots or lines in the image at narrow apertures (or caught the light in backlit subjects)

Thanks again!

[Wayne Fox]

The sensor's clean so all of the spots are from the lens.

Whether your sensor is clean or not, I don't see any way the lightroom image you uploaded could be from spots on the lens.  With a retrofocus design 55mm, how can any dust be sharp enough to result in the pinpoint spots you displayed?  Even dust on the sensor isn't as sharp as that.

Personally that looks like more of an issue with some type of noise resulting from the shot itself, the processing and combination of the dust visualization tool ...

[soylent]

Whether your sensor is clean or not, I don't see any way the lightroom image you uploaded could be from spots on the lens.  With a retrofocus design 55mm, how can any dust be sharp enough to result in the pinpoint spots you displayed?  Even dust on the sensor isn't as sharp as that.

Personally that looks like more of an issue with some type of noise resulting from the shot itself, the processing and combination of the dust visualization tool ...

Not sure noise or processing would cause it, but you've got a good point about the retrofocus design. I was worried I was making a mountain out of a molehill (hence the topic) but I've decided to keep it and get it cleaned up for good measure

[Ken R]

Whether your sensor is clean or not, I don't see any way the lightroom image you uploaded could be from spots on the lens.  With a retrofocus design 55mm, how can any dust be sharp enough to result in the pinpoint spots you displayed?  Even dust on the sensor isn't as sharp as that.

Personally that looks like more of an issue with some type of noise resulting from the shot itself, the processing and combination of the dust visualization tool ...

Yeah, It looks like typical "hot pixels" that apear in image files during long exposures in a lot of backs and some dslrs. Dark frame subtraction gets rid of most of those if not, adjusting the single pixel noise reduction in C1pro gets rid of the rest.

[Chris Livsey]

but I've decided to keep it and get it cleaned up for good measure

I, and I suspect other "dust sceptics" would appreciate you proving us wrong by posting a post clean shot taken under the original conditions.

[soylent]

Hi Chris,

I accepted what you "dust sceptics" said (and I count myself as one; see original post) hence why I'm keeping the lens.

Happy to take and post a spot removal shot with another lens if it helps, but don't see the point?

[Chris Livsey]

Hi Chris,

I accepted what you "dust sceptics" said (and I count myself as one; see original post) hence why I'm keeping the lens.

Happy to take and post a spot removal shot with another lens if it helps, but don't see the point?

You misunderstand, the same lens after return from cleaning, but if you agree the sensor spots you see are not of/from the dust/flakes inside the lens then agree, no point.

I sympathise with the purchase, even from dealers there is often disappointment. I just returned a H grid screen from a Pro Dealer in London which had a large corner flake missing.

[soylent]

You misunderstand, the same lens after return from cleaning, but if you agree the sensor spots you see are not of/from the dust/flakes inside the lens then agree, no point.

Ahhh...gotcha. Although it'll be a sweet irony if it comes back after a service with sparkling clean optics but a bent leaf or something

Thanks to everyone who helped and replied, I'll head back to taking taking photos