Sensor Cleaning

Sensor Cleaning Index:

• Sensor Cleaning In The Beginning
• How To Test If Your Camera Needs Sensor Cleaning
• How Do Scratches And Marks Appear?
• Do Scratches On The Sensor Matter
• Unprofessional Sensor Cleaning
• How To Prevent Smear Marks When Sensor Cleaning
• Which Sensor Cleaning Tools and Materials To Use
• Why Do A Dry Sensor Clean?
• Why Clean The Sensor Chamber?
• Why Is It Important To Inspect And Clean The Mirror Box
• Checking The Focus Screen Area
• Do Sensor Dust Off Facilities Work And How Effective Are They?

Most of us who enjoy photography try to keep our equipment clean and dry. We will gently clean our lenses to remove smears and dust. After cleaning your lens and you are still seeing small dark spots, which can become exceedingly tiresome to spot out in Photoshop, then it may be time for sensor cleaning.

Sensor Cleaning in the Beginning

When digital cameras were first on the market sensor cleaning was only done by the manufacturer. You had to send in the camera, pay a considerable amount of money and wait a week or so, Thankfully sensor cleaning has moved on considerably since then. Sensor cleaning materials are widely available, many camera retail shops and repair agents will also do sensor cleaning. There is a huge number of YouTube clips on how to clean your own sensor. Unfortunately with the increased prevalence of sensor cleaning there are very poor sensor cleaning products on the market, some very dubious sensor cleaning services and not to put too finer point on it some horrific YouTube tutorials on sensor cleaning.

Photographers are rightly wary off delving into the bowels of their camera to clean their sensor. In reality it is not actually that tricky to do so long as you take no shortcuts and follow a procedure with the best materials. We run half day how to clean your sensor with demo cameras to practise on before cleaning your own.

Here at Cameracal we get a lot of photographers who do clean their own sensors but still find they need to on occasion come to us for sensor cleaning. When they have preformed their usual wet swab sensor clean and still the sensor isn’t clean it usually means there are contaminants in there that are above and beyond some dust. Most notable being shutter oil on the Nikon D600, Canon 1Dx Mk 1 and 2 and some Canon 6D cameras splattering onto the sensor.

How to test if your camera needs sensor cleaning?

If you are still unsure of whether or not your camera needs it’s sensor cleaning then a quick test can make the situation clearer:

• Set your camera to Aperture Priority Mode and the metering to Matrix/Evaluative Metering.
• Set the camera to the lowest ISO for example ISO 100.
• Turn off Auto ISO and autofocus.
• Set your lens to manual focus and the aperture to the largest number possible.
• Then simply take a shot of a reasonably well-lit piece of plain white paper making sure you fill the frame.
• Then if you zoom in on the image using the camera’s LCD screen and move around the image. If you see small dark spots then you need to get your sensor cleaned.

Every camera that comes into Cameracal for sensor cleaning will start with this simple test. The process is repeated after the sensor cleaning has been performed and just before the camera is vacuum sealed. This confirms all dark sports and marks will not appear on the customer’s images.

Do Scratches On The Sensor Matter?

One of the first things we do when we receive a customer’s camera for sensor cleaning is to check the sensor for scratches or other marks. We use –the Ezklean Sensor Inspection Loupe has a particular lamp mode (yellow lamp mode) which is exceptional for highlighting marks and scratches.

Do these scratches matter? That depends on many factors such as size, placement and depth of the scratch. Our tests have shown that rarely are these evident in images unless images are taken at apertures of F36 or more (as in extreme macro). It is worth noting that scratches on the sensor actually means scratches on the extremely thin piece of glass that covers the sensor rather than the electronic sensor board.

However any scratches or permanent marks can and often do have a negative impact on the value of your camera if you intend to trade in or sell it. If checked correctly and these marks are evident this could impact the cost of your trade in or sale, possibly even make it unsalable.

How Do These Scratches And Marks Appear On The Sensor?

The reason for the marks or scratches is ultimately down to negligence during sensor cleaning and can be caused by the use of incorrect cleaning materials for example using sensor swabs that haves hard edges, incorrectly lubricated swabs, sand or other small but hard particles that are “scraped” across the sensor glass by a swab. Always use the correct size swab for your type of sensor. For example use full frame sensor swabs to clean a full frame sensor. Always use swabs that have the cleaning lint folded and crimped rather than glued or welded. In some cases a blower brush, which has a plastic tip, has been thrust into the sensor chamber. We have even seen evidence of cleaning tissues or clothes being used to clean the sensor glass. In this case it only takes for the tissue or cloth to be contaminated by one grain of dirt or sand and the damage is done. There will be some reading this information who have successfully completed their own sensor cleaning despite the advice contained here and as stated sensor cleaning is usually not that difficult so long as you use the correct material and process because it will only take the smallest of deviation from this to potentially scratch your sensor. Maybe not the first few times but sooner or later. What we are stressing here are materials and process should prevent that from ever happening. It is this simple chance factor that we want to eradicate.

Unprofessional Sensor Cleaning

Historically we have found that most damage to sensors is done not by camera owners but by camera shops doing the sensor cleaning as rarely do they perform this delicate task properly, often in the wrong conditions and using inferior products or techniques (it has also been known for them to reuse swabs over and over again with previously contaminated swabs causing problems). If you consider the chance factor above and consider sensor cleaning being performed incorrectly day in day out then it's like they are playing Russian roulette with YOUR sensor. Read more on 'How NOT to clean your sensor"

How to Prevent Smear Marks when Sensor Cleaning 

The other problem that occurs when sensor cleaning is that of smear marks. This is something that we see on a regular basis. Not from our own sensor cleaning but customers bringing in their cameras with smears on their sensors after having cleaned them or paying for them to be cleaned. Smearing is generally caused by the over use of water based fluids when sensor cleaning. Water based fluids are   slow to evaporate. We primarily use an alcohol based cleaning fluid for sensor cleaning. Once a swab has been saturated this is then transferred to the sensor glass and thus smeared over the surface area of the glass. Any residue left quickly evaporates with alcohol based cleaning liquids. We do use other liquids when we encounter unusual contaminants but 90% of our sensor cleaning is done with this liquid. It is worth noting that as this liquid is alcohol base, as present you cannot take it onboard a flight. Also, keep the time the lid is off to an absolute minimum.....it really does evaporate very quickly!

Which Sensor Cleaning tools and materials to use?

As mentioned before the sensor cleaning process is not that difficult so long as you use the correct tools and materials and rigidly follow the process. This section is about the tools and materials we use and after decades of experience believe they are the best on the market.

Sensor Inspection -With many years of cleaning sensors our team here at Cameracal HQ have finally found a sensor cleaning loupe that just blew us away. Our search is over with the arrival of the EzKlean sensor inspection loupe.

Over the years we have tested so many inspection loupes both cheap and expensive. The only loupe we use now it the Eziklean sensor loupe. It's small and compact, it's brightness and magnification is just as good if not better than loupes three times the price. It also has a yellow light setting that is perfect for identifying marks and scratches.

We are in fact so impressed by the performance of this product that we are the official distributors for this product here in the UK and a such have supplied many different repair agents (including Hasselblad) and other individuals keen to use the best product for the job.

A loupe has become an important item in a photographer's kit bag. It only takes a few minutes to check you sensor and confirm if it is clean or needs some attention.

Brushes - If a brush is to be used for sensor cleaning it is vital that any loose bristles are extracted from the brush head. If this is not done loose bristles will fall into the sensor chamber and cause further contamination. Once any loose bristles are extracted it is vital to “charge” the brush by blowing filtered air from a filtered blower over the brush hair. This action creates a static charge which picks up dust and other small particles when moved over the sensor glass. As with the whole sensor cleaning process it is vitally important to be careful. Take case when inserting the brush into the sensor chamber. If guided incorrectly it is possible to pick up grease or other lubricants from the mirror box or shutter unit. This will then have the effect of smearing this contaminant over the sensor glass and making the sensor cleaning processes significantly longer. Once this has been done the brush has to be cleaned properly before used again on the next sensor clean. If not cleaned the contaminates will be transferred back on to the sensor.

Blower - Another tool that has long been in the photographer's kit bag. More commonly with a brush on the end but in the digital age a blower is essential. We use the VSGO blower. It has a built in filter to ensure that only clean air is blown into your camera chamber. This blower is supplied with user replaceable filters (6 in total) and two rubber nozzles, one being smaller / more compact nozzle which is ideal for travel purposes. Both nozzles are also made of soft pliable rubber which will prevent damage if mistakenly thrust into the sensor chamber Always tip the camera body upside down when using the blower to any debris is helped out by gravity.

Compressed Air - NEVER use it at any time during a “dry sensor clean”. Cans of air propellent work by converting a liquid agent into air. If the can is not held in an upright position (as in tilted at an angle) the result being that water vapor is propelled out of the can and contaminates the sensor glass. This again leads to smearing and sometimes worse (because of the force of the water vapour this can sometimes find its way through small crevasses at the sides of the sensor glass and contaminate the sensor behind.

Sensor Cleaning Swab - There is a large range of sensor cleaning swabs in the market. Most are not good and at best make the task harder and at worse increase the risk of damaging your sensor. Always purchase the correct size swab for your sensor. They are designed for a single pass and need to cover the whole of your sensor.

Full Frame Sensors

Cropped Sensors

Micro4/3rds Sensors 

Why Carry Out a Dry Sensor Clean?

There are several reasons to undertake a dry clean before a wet clean. The two primary reasons are:

1. Most “free floating” contaminant be it dust or other pollutants which do not have a sticky residue can be eradicated by way of a dry clean be it using a filtered blower or a device such as the  Dust Aid Platinuim Sensor Cleaning kit which can gently lift said contaminant off the sensor without harm or leaving any residue. If this is successful then it bypasses the need for a wet clean thus saving time and ultimately cost.
2.  More importantly if contaminant such as sand or grit has found its way to the sensor a wet clean will only result in scratching of the sensor glass as the contaminant is dragged along the sensor glass by the swab. This is one of the biggest causes of damage. Once a sensor has been scratched the damage has been done.

The safest way by far would be to gently pick up these contaminants by using the Dust Aid Platinuim Sensor Cleaning kit, once eradicated and the sensor checked and repeated if required a wet clean can be undertaken if deemed safe to do so.

Why Clean The Sensor Chamber?

The Sensor chamber is often referred to as the garbage / rubbish collector as the walls are often covered with a felt like material which traps any contaminant that has entered the sensor chamber, this method is effective in terms of trapping contaminant but ultimately with movement of the camera, vibration from the shutter and mirror mechanism etc this contamination ultimately ends up falling on to the sensor area.

With Canon and Nikon felt is rarely used on the bottom part of the housing and this is often where all the contaminant collects, again only to fall on to the sensor.

It is therefore important to clean these areas whilst undertaking a dry or wet clean (or both) as this is often preventive medicine and can elevate future problems.

Why is it important to inspect and clean the mirror box?

Contaminations such as sand, grit, pollen and other heavy particles often collect in the mirror box area, this contaminant often works its way backwards to the sensor chamber and ultimately ends up on the sensor itself. It can also damage shutter blinds in the process.

Grease from lubrication of the mirror box can also be a problem and is known to effect certain models of camera (Nikon’s D600, Canon’s 1DX MK 1 & Mk2 models). The problem arises from over lubrication of the mirror / shutter mechanism which is then transferred to the sensor and “pools” at the top of the image (contaminant is found at the extreme bottom edges of the sensor – images are reversed hence why they appear at the top of the images).

This is a well-documented problem and reference to the problem can easily be found by conducting a search on google – Nikon D600 / Canon 1DX / 1DX Mk2 oil problems. As yet there is no solution to the problem other than checking the sensor on a regular basis and conducting a “Dust off” (Nikon) or Dust Delete Date Reference (Canon) once a successful sensor clean has been undertaken. This problem has been known to effect other models of camera and can cause ongoing problems. If you have a feeling that your model is affected by this problem, we would suggest you contact the camera manufacture with examples of the problem.

Checking the focus screen area

Rarely are focus screen areas sealed against dust and other pollutants. As a result it is quite common for dust and other contaminant to collect on the underside (or both sides) of the focussing screen or worse behind the eyepiece.

Is this a problem and will it affect your images?

Popular to belief, NO, this is more of an annoyance more than anything, any specks seen through the viewfinder of a mirrored DSLR WILL NOT appear on your captured images.

Can these specks been eradicated from the viewfinder?

Ultimately this depends on where the dust spots are located.

In order to ascertain where these dust spots are and if they can be eradicated, undertake the following simple task:

1. Take the lens off the camera
2. Point the camera up towards a light source and look through the viewfinder
3. If the spots are out of focus then they are found on the bottom part of the focus screen in the mirror chamber itself and can be eradicated with caution (see below)
4. If the dust spots are in focus then the they are trapped on the other side of the focus screen or worse trapped in the eyepiece glass elements themselves. If this is the case it is near impossible to eradicate the problem without either removing the focus screen itself (on models that allow this) or to return the camera to a qualified repair technician for a partial dismantle of the cameras top plate and or removal of the focus screen. Do not attempt to remove the focus screen yourself (on models that allow this facility) as this often leads to damage of the screen and further contamination of the focus screen area. Any attempt to “blast” the dust free using a can of compressed air will ultimately result in damage to the focus screen by extreme force or by liquid propellent from tbe gas inside the canister.

Note: if you do attempt to clean the underside of the focus screen as in c) please be sure to use a filtered air blower which has a soft tip, this prevents any damage to the screen if inserting the tip of the blower into the top part of the mirror chamber. We would suggest using one of the JJC Professional Filtered Air Blowers which have one of these plastic tips.

Do sensor dust off facilities work and how effective are they?

There are effectively two types of Dust off / Dust delete methods, both of which ultimately work in the same way in terms of requiring the end user to record a test shot of a featureless white sheet of paper. This reference image is stored within the camera and added to each and every shot taken by the user. This shot is then used a “clean image” and used a reference to subtract any spots from the users images. This process requires the camera to be connected to a computer and the images to be downloaded and loaded into a software application (either Canon’s Digital Professional Pro or Nikon’s NX-D software).

For a more detailed explanation of how this “in camera subtraction” facility works please refer to the following links –

Nikon;s Image Dust Off

Canon’s Dust Delete Data reference

Note it is important to mention that the reference shot mentioned above is undertaken when:

1. The camera is new and first unboxed.
2. A successful sensor clean has been undertaken.

Sadly this is often not the case and as such is rarely of use.

Cameracal Sensor Cleaning Service - Cleaning Cabinet with Hepa filters - Blog Post

Whilst having your camera (s) and lens calibrated we are also, for a small additional charge, able to check your sensor and if needed take advantage of our exceptional sensor cleaning service. Should we find any evidence of dust, pollen or other foreign matter that the dust off facility* is unable to eradicate we can offer a sensor cleaning service which exceeds that offered by the camera manufacturers themselves.

We use only the finest products to ensure your sensor is dust and pollutant free and will also create a new Dust Verification (Canon) Dust Off (Nikon) reference should you experience problems in the future.

Sensor Cleaning Service Customer Report

• Sensor Checked for Scratches / Marks
• Dry Clean Undertaken
• Wet Clean Undertaken
• Number of Swabs Used
• Sensor Chamber Inspected / Cleaned
• Mirror Box Inspected / Cleaned
• Focus Screen Area Checked / Cleaned
• Dust Verification Reference Created

If left and not checked dust and other foreign matter can often spoil images and even with careful software cloning be unrecoverable.

As part of the service we can also provide a report which analyses the number of dust spots / foreign matter particles on your sensor and at what apertures these would be visible at.

*Dust off facility found on Canon / Nikon models works by applying a small voltage to the sensor glass which has the effect of vibrating any dust particles from the glass, dust is then collected by a sticky adhesive strip at the bottom of the sensor chamber. Note this is not effective against pollen, diesel or other sticky airborne residue which has a tendency to stick to the sensor glass.

We use the highest quality sensor cleaning swabs and fluid for :

• Micro 4/3rds cameras
• Cropped sensor cameras (APS-C and APS-H)
• Full frame cameras
• Medium format cameras

We only use appropriately sized sensors for each size of sensor thus ensuring the least number of passes on the sensor.

At CameraCal we are confident that we provide the most comprehensive and thorough sensor cleaning service available in the UK. Below are our reasons why. 

The most comprehensive sensor cleaning service available.

1. Test shots using Focal to determine the degree of dust contamination. Shots are taken at every aperture to demonstrate at what apertures dust is evident.A detailed report of any dust spots / foreign matter on the sensor and the apertures these would be problematic. Sample report

2.  All sensor cleans are carried out in our unique dust free sensor cleaning cabinet complete with extractor fans and hepa filters

3. A thorough sensor clean us undertaken using only the best products available (correct sized sensor swabs and smear free fluid) 

4.  Cleaning of the  sensor chamber using the appropriate swabs.

5. Cleaning of focusing screen if required using the appropriate swabs (focusing screen is removed to clean the prism – model specific).

6.  All actions carried out are itemised and reported on.

7. Creation of a dust verification reference point in camera to prevent problems in the future (Canon and Nikon only)

Sensor cleaning costs:

Micro 4/3rds (Olympus and Panasonic) £36-00 per camera.

Crop sensors – (Canon 1.6x & Nikon 1.5x)  £36-00 per camera.

Full Frame sensor = £56-00 per camera.

Medium Format size sensor = £56-00 per camera.

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Workshop - How To Clean Your Sensor : £79-00 per person.

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