Cleaning the rear element of a lens

[ChrisR]

As some of you may know, I sold the Minolta M-Rokkor 40mm lens that I had bought with my Leitz Minolta CL, "elsewhere", as they say. My description was:

Minolta M-Rokkor 40mm f/2 manual focus rangefinder lens with front and rear (after market in the latter case) lens caps, plus a Hoya 40.5mm yellow filter (K2) and a 40.5 to 49mm step-up ring. Fits a standard Leica M-mount. Suitable for Leica CL, Bessa R3A etc. This lovely sharp lens is tiny and light, and is in excellent condition, no marks or scratches that I can see.

Shortly after receipt, the buyer complained there were marks on the rear element, and eventually we initiated a return. The reason given was

Doesn't match description or photos

It arrived an hour or so ago, so refund done (including his postage both ways). However, I was pretty disappointed when I looked closely at the lens. It took me several minutes to see anything, and eventually I could see the tiniest speck at certain angles. Anyway, that's all by the by, water under the bridge etc.

I'm afraid I then got out my lens brush and tried (very gently) to brush away the tiny speck that I could see. The result is that I now DO have marks on the rear element. I find it hard to believe that I could have damaged the rear coating with so gentle a brush, but it's entirely possible I suppose. I was wondering if there might have been some other residue on the rear element that has taken a mark. But before I do anything else (and possibly make things even worse than they are now) I thought I'd better tap the accumulated wisdom within this forum.

Help!

 

[Mr Bump]

isopropyl alchahol dabbed on with a ear bud
its still glass at the end of the day

 

[Strapps]

I've cleaned a couple of elements, inside of a front and a rear and I didn't treat either of them with kid gloves. I couldn't because that didn't shift anything! This was mold removal though, don't know if that makes a difference.

I regularly clean my lenses with a lens pen, which has a pad at one end for polishing and again, that's never left a mark which I couldn't wipe off.

Without knowing your lens better, I'd probably give it a rub with a microfiber cloth after ensuring any grit or dust had been blown or brushed off; any coating that can't be wiped is next to useless. That said, there may be something special about this lens which I'm not aware of.

 

[Nod]

I'm another who uses the same method on rear elements as I do on fronts. Your tiny spot MIGHT have been a droplet of oil and the brush might have spread that over the rear element - isoprop and a cloth (I use the little tissues that are cheaper than chips!) Try the brush on a clean bit of glass to see if it leaves little streaks, if so, either clean it with a suitable detergent or replace the brush.

 

[ChrisR]

Thanks for the thoughts so far. It does look more like smeared oil than scraped coating to me. I have a large bottle of IPA but not accessible to me at the moment.

Tried the brush on a clean glass but couldn't convince myself about streaks either way. However, it IS 40 years old, so perhaps I'd better treat myself to a new one. (It's the kind where the brush disappears inside on a spring when you take the cap off the back; is the kind with in-built air puffer, but exposed brush, a better idea or worse?)

 

[ChrisR]

Anyone any experience of this Hoodman wet and dry cleaning kit? Found it via a Youtube video...

 

[stevelmx5]

Get yourself to Asda and buy a box of single use glasses lens cleaning wipes for a pound. They have alcohol in them that cleans then evaporates and I use them on all my lenses.

 

[Strapps]

I use a lenspen (that's its brand name) and a rocket blower. Those blower brushes don't have enough puff, at least the ones I've used in the past.

Cotton buds, lighter fluid, IPA, microfibre cloth and lens tissues are the other bits of my cleaning kit.

 

[Mr Bump]

Lidl do the glasses wipes, I think they are pretty much just isoprop

 

[ChrisR]

Needed to make an appointment with my optician, she gave me a couple of Zeiss single use wipes. I had a go and it looks much better. She suspects a slight mark left that I will have a look at tomorrow, when there's real light again!

 

[trevorbray]

Needed to make an appointment with my optician, she gave me a couple of Zeiss single use wipes. I had a go and it looks much better. She suspects a slight mark left that I will have a look at tomorrow, when there's real light again!

Called in the Optician. Blimey Chris, you're taking it too seriously..

 

[ChrisR]

 

[simonblue]

You say you can only see it at certain angles,it could just be a simple flaw in the glass of the lens,it should not affect the IQ of the lens

 

[ChrisR]

Yes I think I'll have to run a roll through the CL with the lens in stress conditions before doing much else...

 

[excalibur2]

For cleaning a lens I usually huff on it then use a soft brush, if that doesn't work then use a cotton bud with either lighter fluid or IPA....I know what you mean about faint surface smearing as with some very old lenses it's not easy to remove to make it look mint and the only logical reason I can think of why some lenses are easier to clean is because of the coating h'mm

 

[realspeed]

Never ever let a cotton bud anywhere near anything to do with photographic equipment, they are too fluffy. Far better to use one of these unless you really want to mess up a lens or sensor. I know far too well the amount of "hairs" they leave



they can be got from any sensor cleaning kit being sold on the internet

look up

Visible Dust Green Corner Swabs

 

[Woodsy]

TBH...

 

[excalibur2]

Never ever let a cotton bud anywhere near anything to do with photographic equipment, they are too fluffy. Far better to use one of these unless you really want to mess up a lens or sensor. I know far too well the amount of "hairs" they leave



they can be got from any sensor cleaning kit being sold on the internet

HuH! You might have a point cleaning the inside of a lens, but for the outside......................................................................................................

 

[realspeed]

Just as good on the outside believe me
can be bought from here

http://www.wexphotographic.com/buy-visible-dust-extra-chamber-clean-swabs-12/p1012099

Brian

I was one of those idiots who tried using a cotton bud and wound up with all sorts of problems which took ages to get rid of. I soon learnt that to clean anything to do with cameras/lenses you have to use the right gear.

so I bought the whole kit while at the focus on imaging at the NEC as the show was back then. that included the Loupe - Arctic butterfly 724 -cleaning fluid and swabs from Speed graphics for £115 back in 2009 in a presentation box.
It is one of the best purchases I made, it has saved me sending away for sensor cleaning so many times and Not having to wait either.

 

[ChrisR]

Interesting Bazza, although both links describe the product (either directly or via comments) as being for sensor or interior chamber cleaning. One comment suggests it's difficult to do a largish area... not sure if that would apply to front and rear surfaces of a lens? I guess they likely wouldn't do any harm.

I've ordered a LensPen following a hint from @Strappy.

Jonathan, I know you have large cameras, but...

 

[NickT]

I think the comments in this thread demonstrate the difference in the attitude to cleaning between digital and analogue photographers. I have no experience of digital cameras but I know that users are very concerned with keeping the sensor clean. With a 35mm film camera then the equivalent of cinematography's 'checking the gate' will suffice. The worst you can do to the one shot sensor (i.e. the film) is put a fingerprint on it. The only things I've used to clean lenses are a camel hair brush and a Spudz cloth, although cotton buds wouldn't worry me too much.

 

[realspeed]

Chris

I tried one of those as well and it left smudges across the lens and the brush hairs came out. Just to prove i have tried the lens pen and also the Hama mini pro version



Nick

I never had any problems with my Viotlander Vito CL 35mm camera to keep the from lens clean either. Those 35mm cameras never attracted dust like the digital cameras of today do.

Like most electronic equipment dust is the enemy and DSLR cameras are very prone to it.

The problem is if you get dust on a sensor sending away for cleaning is expensive and time consuming to say the least.
I did some time ago write about how I go about sensor cleaning but everyone has their own ideas.

Another thing I avoid like the plague is a rocket blower even though some swear by them. My thoughts are if you have dust on the sensor then sure as hell you have dust inside the camera body as well.
A rocket blower will more than likely stir up this area as well causing even more dust problems that starting out with. So I prefer to use the Arctic butterfly which attracts dust to it

Lens cleaning is slightly different but a good micro cloth should sort out most problems but dust within the lens barrel I would send away to get cleaned

I suppose having done photography as a hobby for the last 50 or so years you make mistakes and learn from them, I know I have and still make a few as well. Oh and my first camera was a Brownie 127

 

[excalibur2]

I think the comments in this thread demonstrate the difference in the attitude to cleaning between digital and analogue photographers. I have no experience of digital cameras but I know that users are very concerned with keeping the sensor clean. With a 35mm film camera then the equivalent of cinematography's 'checking the gate' will suffice. The worst you can do to the one shot sensor (i.e. the film) is put a fingerprint on it. The only things I've used to clean lenses are a camel hair brush and a Spudz cloth, although cotton buds wouldn't worry me too much.

If you want to use cotton buds then last time I went to Poundland you can get Johnsons....much bigger heads then el cheapo ones.

 

[excalibur2]

Just as good on the outside believe me
can be bought from here

http://www.wexphotographic.com/buy-visible-dust-extra-chamber-clean-swabs-12/p1012099

Brian

I was one of those idiots who tried using a cotton bud and wound up with all sorts of problems which took ages to get rid of. I soon learnt that to clean anything to do with cameras/lenses you have to use the right gear.

so I bought the whole kit while at the focus on imaging at the NEC as the show was back then. that included the Loupe - Arctic butterfly 724 -cleaning fluid and swabs from Speed graphics for £115 back in 2009 in a presentation box.
It is one of the best purchases I made, it has saved me sending away for sensor cleaning so many times and Not having to wait either.

Thanks for your input Bazzo as all knowledge is valuable, but for filmies the lens is not that important to maintain in mint condition from dust as many tests have proved the lens can take a lot of abuse from inherent bubbles to scratches (the rear lens is most important to prevent abuse) and still give excellent results (lots of dust usually reduces contrast)......we (well me) are more interested in a clear view finder and having a dirty mirror doesn't help and the pentaprism can be a nightmare to take apart and clean also the inside glass of the viewfinder.

http://www.lensrentals.com/blog/2008/10/front-element-scratches

 

[Mr Bump]

I think the comments in this thread demonstrate the difference in the attitude to cleaning between digital and analogue photographers. I have no experience of digital cameras but I know that users are very concerned with keeping the sensor clean. With a 35mm film camera then the equivalent of cinematography's 'checking the gate' will suffice. The worst you can do to the one shot sensor (i.e. the film) is put a fingerprint on it. The only things I've used to clean lenses are a camel hair brush and a Spudz cloth, although cotton buds wouldn't worry me too much.

exactly my most expensive 35mm lens was £125 and my most expensive MF lens about £220.
Compared to digital crazy world of cost......

I prefer the johnsons ear buds as well

 

[steveo_mcg]

Must be nice to be wealthy.

I Don't think I've spent more than £150 on a lens for any format.

 

[puggie]

I clean lenses for our laser and occasionally cinema stuff at work (Very expensive lenses, I could but the whole canon L catalogue and have change for the bus home for some of our pieces of glass!) I use very pure iso-propanol and some 'optical wipes' which are basically a thin soft lint free cloth. I'd be wary of using anything paper based as a cleaning cloth (tissue etc) at home I'd probably be raiding the first aid box for lint free dressings or similar.

EDIT: I also got miffed with flebay when I sold a canon zoom (28-105mm) which I described as dusty and included pics, the buyer returned it for being too dusty! maybe he just didn't want the lens and saw it as an easy way to return??

 

[NickT]

I prefer the johnsons ear buds as well

I hate to take this off-topic but a couple of months ago I thought I was going deaf. So after being nagged I went to the surgery where the practice nurse gave me an ear syringing for the first time in my life. The result was a huge improvement and I asked the nurse about future DIY cleaning with cotton buds. The answer was 'DON'T'. A Google search for "ear" + "cotton buds" will confirm that advice many times over.

 

[ChrisR]

EDIT: I also got miffed with flebay when I sold a canon zoom (28-105mm) which I described as dusty and included pics, the buyer returned it for being too dusty! maybe he just didn't want the lens and saw it as an easy way to return??

Yes, I suspected that too. I started writing a s***ty email to the "buyer" along the lines of "well, it looks pretty damn pristine for a 30+ year old lens to me, good luck with finding an absolutely perfect one for that price", but thought better of it. Do feel better now, though. Oh, his first offer was just over half my asking too, though I didn't accept it. Cheeky blighter. Annoyed that I'd already left positive feedback for him because of quick payment. Grump.

 

[ChrisR]

I hate to take this off-topic but a couple of months ago I thought I was going deaf. So after being nagged I went to the surgery where the practice nurse gave me an ear syringing for the first time in my life. The result was a huge improvement and I asked the nurse about future DIY cleaning with cotton buds. The answer was 'DON'T'. A Google search for "ear" + "cotton buds" will confirm that advice many times over.

The advice I've heard is: never put anything smaller than your elbow in your ear!

 

[excalibur2]

I hate to take this off-topic but a couple of months ago I thought I was going deaf. So after being nagged I went to the surgery where the practice nurse gave me an ear syringing for the first time in my life. The result was a huge improvement and I asked the nurse about future DIY cleaning with cotton buds. The answer was 'DON'T'. A Google search for "ear" + "cotton buds" will confirm that advice many times over.

...a cotton bud could push the wax into your ear compacting it if used incorrectly. I use cotton buds away from the eardrum to clean the area as I'm sure if in company it doesn't look very nice if you have brown wax showing in your ears

 

[Strapps]

EDIT: I also got miffed with flebay when I sold a canon zoom (28-105mm) which I described as dusty and included pics, the buyer returned it for being too dusty! maybe he just didn't want the lens and saw it as an easy way to return??

Some buyers think that a description of "dusty" means the seller is trying to avoid returns for a couple of specs so they'll get a bargain. Send them a lens that's actually dusty and they're miffed because it's not the mint-minus steal they thought they were getting.

Wait until you get an ebayer returning a lens because, and I quote, "I didn't read the description and now I have and I don't want it".