Technical

How to Clean Camera Lenses

Article text
The superb wide-open aperture performance and low distortion of Hasselblad's 60mm Distagon lens. And it was filthy - in need of a thorough clean!
While there are a mix of many “old wives tales” and outright illogical (if not dangerous) suggestions about how to clean camera lenses; the best and equally safest method is simple.

There are also some very sound “rules” and tips that one should always keep in mind that help avoid enormous disappointment and expense if you get it wrong.

So, firstly I’ll outline how you should clean camera lenses; then I’ll outline the basic rules to always follow and finish with some background tips.

Before you begin:

Overall, cleaning a camera lens is simply a logical process and a disarmingly simple one at that:
1. You must avoid rubbing a surface that has any type of grit (visible and not so visible) on it.
2. What you use to rub the surface must be incredibly soft and clean and it must have enough depth to allow any particles to migrate away from the cloth’s surface while it’s being used.
3. The lens surface, pentaprism mirror and focusing screen you are about to clean must have any possible amount of grit (obvious and minute) blown off its surface before you use any type of cloth to rub the surface clean – or, obviously enough you will rub that grit into the lens surface.
4. The softest cloth type in this the 21st century is, by a long margin, microfibre, of which there are many variants. If you are in any doubt about that just keep in mind that microfibre is at least 10 times thinner (read finer) than a human hair!

What you will need (not negotiable!):

1. A rubber lens blower – not canned air, just a simple long nose lens blower;
2. A lens brush – the softest you can find;
3. A plush microfibre cloth – not the thin nasty overpriced ones you get in camera stores, but the thick plush type that has a teased looking surface (it looks and feels plush);
4. A re-sealable plastic bag to keep the 3 items in when not in use.

Little red car.
Little red car.


* This image was taken a few minutes after the image that leads this article - with the same lens (borrowed) and in the same dire need of cleaning!

How to clean a lens, filter, mirror or focus screen.

In this order without exception:
1. Examine. Carefully examine the surface and corners to see where there may be any grit;
2. Blow. Using a lens blower, always blow across the surface towards the outer edges to remove any solids (grit, hairs and dust) – even if you can’t see any grit on the surface;
3. Brush. Using the lens brush, gently brush across the lens surface out towards the filter mount taking care to flick out any grit there too.
4. Wipe. Gently use the microfibre cloth to (I stress gently!) wipe the lens (or mirror or focus screen) surface from the centre outwards in a circular movement. The first wipe must be very light just in case any grit has remained on the surface after blowing and brushing across it. Re-inspect the surface and if there are still marks (and only if there are still marks to remove), repeat the wiping with slightly increased pressure after, and only after you give the cloth a shake to release any trapped grit.
5. And if necessary and strictly for lenses only. If, and only if the above process has not removed any marks then use a camera lens optical company’s lens fluid – always apply the fluid (preferably via light spray) to the cloth – not the lens! It is worth paying a premium for lens company fluid only because if it damages the lens coating in any way, you will have product liability recourse regardless of the company’s liability exclusions.

Smoko.
Smoko.


* Immediately after this photo was taken, upon removing the lens I noticed 2 specks sitting on the rear element. Careful examination of the negative failed to show any visible impact.

The Rules:

1. Never use cotton cloths or any other non-microfibre cloth for that matter. They are too abrasive and unnecessary in this era of brilliant microfibre technology.
2. Never ever use lens tissues – these rely os exceptionally hard lens coating to avoid a sand paper effect. The risk is totally unnecessary today.
3. Never ever ever use a normal household tissue.
4. Do not breath or huff on your lens – microfibre cloth do not need lubricants to work effectively; your breath is moist and contains acids and bacteria.
5. Always regularly wash your microfibre cloth to remove building up dirt and grit as well as the oils from your hands.
6. Don’t let your cloth roll around lose your camera bag – it will gather grit! Keep it in a re-sealable plastic bag.

Some tips:

1. It’s best to mark one side of your microfibre cloth as the cleaning surface to avoid wiping the oils from your skin onto the lens surface.
2. A plush microfibre cloth allows micro grit somewhere to go rather than sit on the surface only to scratch your lens;
3. Try to ensure your blower is the type with a soft long nose so there is less risk it will knock and mark the lens, mirror or screen;
4. Clean lenses, mirrors, filters and screens as infrequently as possible – every clean has risks and small amounts of dust etc. have no adverse effect upon image quality;

Keep in mind that it is rarely necessary to “thoroughly clean” a camera lens – normally a quick blow will do the job, and if some grit remains on the surface a quick brush will often complete the job. Do not be tempted to wipe the lens just for the sake of it. Anal retentive behaviour rarely pays off when it comes to cleaning lenses.

Likewise it makes sense, as a matter of course, to give all your lenses a quick blow after a “shoot” – front and rear elements. If you have filters on your lenses and there were not removed during the “shoot”, then treat them to the same quick blow. This way when you head off for the next shoot you’re prepared in advance.

Finally, prevention is the best cure! While I do not promote the use of filters 100% of the time for obvious reasons of potential image degradation; I do recommend filters be used when the environment is “risky” – low or high risk. It may just be a hot north wind day around an area of building works adding risk of grit in the air; or it may be a high risk location near a beach. Just be alert and use common sense.

Three Spies.
Three Spies.


* There is no way that the marvellous Carl Zeiss "like new" lens that took this image will ever have anything other than a plush microfibre cloth touch its glass elements while I own it!

PS: About Microfibre Cloths:

Of course these are a 21st century God-send - the best and safest way to clean ANY surface with the lowest possible risk of scratching.

But for camera lenses take the time and care to select the optimal microfibre cloth for the job. And then care for the cloth so that you minimise the risk of adding foreign abrasive matter that can turn the best cloth into sandpaper!

So, here are some tips about care and selection of your microfibre cloth:

1. Wash out regularly in warm water with mild detergent and rinse in warm water thoroughly. Then put it in the spin mode of your clothes washer and hang out to dry;
2. Do not add fabric softener when washing it;
3. The BEST microfibre cloth to use is NOT the thin type lens companies and camera stores sell at rip-off prices. The VERY BEST types are the plush super soft thicker pile types. Just like the best sold in auto-shops for paint polishing type. The car restorers are hugely fussy about causing rub marks on fresh new paint and paint is not as hard as your lens coating;
3. The plush type of cloth helps to ensure any micro-grit moves deeper into the pile and not sit on the surface waiting to scratch your glass!
4. Mark one side of the cloth as your cleaning side - that way you will not rub your skin oil into the glass;
5. Rinse your cloth regularly; wash occasionally - the former frees the cloth of grit and the latter removes oily dirt build-up;
6. Keep the cloth in a clear re-sealable bag when not in use for obvious reasons.

If you have any doubt about what type of microfibre cloth to buy and my recommendation of the plush type (and the best auto plush pile ones are CHEAP - 1/2 that of the camera store cloths; 10 times better and safer and about 10 times bigger!), get your dirty sunglasses or spectacles and give them a quick wipe with the cloth (don't bother to rinse the glasses first as you should normally do) - bingo, you have brighter cleaner glasses than ever before!