[Deimos]

Hi All,

I recently purchased a Sigma 30mm 1.4 from fleabay. Described as Mint-Like New (of course)

When I received the lens I noticed there is what looks like a large cleaning mark on the front element. It is circular and blue and you can see it only at certain angles. It takes up maybe 70% of the front element.

It looks like the lens was cleaned with a t-shirt or thumb or something, a blue smudge/smear maybe one layer of the MC? It doesnt look like the MC was penetrated to the glass, will this be an issue or no problem at all?

If it is going to cause issues I would rather return the gear as it was described as MINT.

Damn fleabay, I dunno why I ever stray from the marketplace...

[Anvh]

What happens when you clean it, or don't you never clean a lens?
Try to see if it makes a difference.

[Medium FormatPro]

A bit off topic...

Even with the best multi-coating on any lens; and even though a filter might vey gradually reduce the lens optical ability/capability; ths would be one of the many reasons i strongly suggest some type of filter on the front element.

Sure the odds say that with todays technology, with todays coating on the lesn'; that it is much more difficult to damage the front element of most lens', but...

With a good quality filter (most of them have brass rings); it trequently helps the tone of the image (although I've also seen people use polarizing filters for protecting the lens - even though it reduces light gathering a small portion). It also helps to protect the lens element against most forms of moisture; help protect againt bumps, and keeps most everything off of the front element.

Also which would someone reather be cleaning on a regular basis; the front element of any lens - or a filter which can be replaced if worse comes to worse.

...And yes i ave seen people clean their photography gear with optical only items - and then even that leaves extremely minor damage to the front element. To me that front filter is worst it as being a type of insurance.

If it is going to cause issues

Please let us all know how your cleaning efforts turn out.

[Wheatfield]

Staying off topic, I sold cameras at the retail level for around 10 years. The most common damage I saw was cleaning marks on the glass caused by people who had OCD about dust.
It seems to me that it has only gotten worse over the past 20 years since I left that part of the industry. I never use "protective" filters and I almost never clean lenses. The only time I clean the glass is when there is an actual smudge where something has touched the element by accident.
Dust on a lens isn't going to affect it's picture taking ability unless there is a ridiculous amount accumulated, in which case a soft brush or compressed air/canned gas is a better way to remove it.
Also, a well washed old t-shirt is one of the best fabrics for cleaning lens glass if smudges have to be removed.

[Anvh]

Also which would someone reather be cleaning on a regular basis; the front element of any lens - or a filter which can be replaced if worse comes to worse.

You don't wear glasses if you say something like this.

Spectacles have the same kind of coatings and i clean mine almost on a daily basis, no problem at all so far after 3 years....


Besides some filters are very hard to clean, i believe some of hoya are quite hard.
I only use B+W MRC myself and they work great, same as the SP coating on Pentax lenses, also very easy to clean just one gently wipe is often more then enough.

[Anvh]

+1 for wheatfield.
Clean shirt also does wonders when i need to quickly clean my glasses, i think everyone that wear glasses does that sometimes.

[Deimos]

Forgot to mention, I tried to clean it with lens cleaning wipes (dry). It looks like it is something that could possibly come off if I used a cleaning solution, but the lens cleaning wipes did nothing, they didnt even change the look of the smudge mark at all (and they usually remove greasy finger prints, etc, so I would think I would have at least seen a change in the smudge if it could be removed). Good to know about the t-shirts

The only thing I have at the moment is no-name eyeglass cleaning solution which I hesitate to use even though glasses are MC, as I have no idea whats in it. Ill have to pickup some lens cleaning solution and try

Assuming I cannot get this smudge off, do you guys think this would have some ill effect on IQ, in theory?

---

Last edited by Deimos; 04-18-2012 at 07:16 AM.

[altopiet]

You don't wear glasses if you say something like this.

Haven't you seen the new filters for glasses, if you change frames, they automatically change to the new shape? Just kidding

Another +1 for wheatfield.

[Ubuntu_user]

Deimos, do you have a lenspen? If not, it does amazingly at removing marks.

[Deimos]

Deimos, do you have a lenspen? If not, it does amazingly at removing marks.

I dont but maybe I will pick one up, looks like I need to try some sort of wet solution to be sure whether I can remove this or not

[Ubuntu_user]

I dont but maybe I will pick one up, looks like I need to try some sort of wet solution to be sure whether I can remove this or not

I've always been a little weary of wet solutions... If there's a real tough spot, I just breathe on the lens so that the front element fogs over and then quickly use the lenspen. That little bit of moisture helps it work even better.

[Deimos]

I've always been a little weary of wet solutions... If there's a real tough spot, I just breathe on the lens so that the front element fogs over and then quickly use the lenspen. That little bit of moisture helps it work even better.

Hmm I see I thought it was a wet solution. Its prob a bit like a better/reusable version of the lens cleaning wipes im using. I have already tried the hot breath/lens cloth, no change, which is why I am thinking this is MC layer damage.

[altopiet]

Would it possible to post a photo of the mark?

[RioRico]

If it is going to cause issues I would rather return the gear as it was described as MINT.

If it has a large cleaning mark, it ain't MINT. You have grounds to return it.

[Deimos]

Does anyone know the likelihood of what I have described causing a real issue with IQ. I bought cross-border so it will be a bit of a PITA to return. If this is unlikely to show in photos ill be fine with it. I havent seen anything off in my shots so far but maybe this would only be an issue with certain situations like into the sun or something

Would it possible to post a photo of the mark?

Thats the problem, I only have one camera!

It really just looks like a smudgey blue layer of multicoat that wont clean away, ill see if I can get a shot somehow