SD14 Sensor Cleaning

akv

Well-Known Member
Hi All,
I was wondering if anyone had any links or references for cleaning the sensor on the SD 14. I've tried searching the forum but didn't find anything. I'd just like to see how it's done before I do it on my own.
Thanks!
 

netzuser

Banned
Hi akv,
can you read German?
This topic has been discussed almost endlessly and comes up every few month in the German section of this forum and others as well.
To keep it short,one of the preferred techniqes is to use a bellows first.
If the dust or other particles cann´t be blown off,the 2.step is to clean
the sensor with isopropyl and cotton swabs.
Take good quality cotton swabs (Q-tips),the cheap ones may leave fluffs,
apply a drop of isopropyl to it.Do not have the swab to wet,a drop will do.
Go gently from one side of the sensor to the other.
Only go in one direction,i.e.always from left to right.
Check the result with the dustprotector still left out.
Repeat the cleaning if nessesary.
This is one of the easiest and cheapest methods.
There are a lot of other proposals,but this one has been proven to be effective.
Good luck
Uwe
PS:Sorry,my English still is bumpy :eek:
 

akv

Well-Known Member
Thanks Uwe,
Unfortunately I can't read German (All I know is Ich liebe dich!). I've seen lots of post over the web that explain things but I was hoping to find images or a video. The manual doesn't go into much detail really and I'm afraid of damaging the IR cut filter, since it is a VERY delicate piece, from what I've read online. I'll just keep looking or if you can provide a link to the German pages I could try and use Google Translator to translate them. Hopefully someone will upload a video of the process onto Youtube.
Your English is very good! Better than my German!
Thanks again!
 

netzuser

Banned
Hi akv,
if your sensor doesn´t need a cleaning urgently,wait a few days until Klaus_R is back online.
He is the expert on sensor cleaning.
I don´t think it is a good idea to have Google translate the German postings.
It will misslead you.
You will end up in a limbo.:confused:
Regards
Uwe
 

jasonh

Well-Known Member
The dust protector isn't difficult to remove, and I don't think it's really that fragile. Just be gentle with it.

There is a ridge on the upper portion of the circle. gently use your thumbnail to push on this ledge towards the top of the camera. Once the filter is loose, hold a microfiber lens cloth in your hand and turn the camera over onto your hand and the filter should fall out onto the cloth.
 

toisondor

Well-Known Member
I wonder if it is even possible to remove all the dust completely. My SD14 was only 2 days old when I already noticed two or three particles (at f22).

After a few weeks, I got up the courage to remove the dust protector and I spent over an hour with a blower trying to get them out, taking test shots, repeat, etc. The specs moved around, but I just couldn't get them completely off (static, I guess). I've decided to live with it for now since it's only a problem at smaller apertures. Maybe I'll try the isopropyl.

As for the IR filter/dust protector, I just followed the manual and didn't have any problems at all. The bottom of the filter is simply hooked under the rim of the opening, and pushing up in the direction of the arrow at the top releases it.

Replacing the filter is not the exact reverse of extracting it. Place it in the camera in its proper location and press the bottom edge down (e.g., towards the sensor) until it clicks back into place. At first it doesn't seem like there's much holding it in place, but that's the design.

BTW, I'm no expert. My SD14 is not even 2 months old. Let those with more experience correct me.

Jesse
 

akv

Well-Known Member
Thanks Jesse,
The same thing happened to me, I don't think it was even a few months when I got dust specs on my sensor. I think once I've built up enough courage I'll give it a try. Maybe on future Sigma SD models they'll figure some way of better protecting the sensor from dust.
I guess eventually I'll just have to dive in though.
 

Steaphany

Well-Known Member
Be careful regarding your source for isopropyl alcohol.

Do not use "Rubbing Alcohol" which could be either isopropyl or ethyl alcohol combined with other solvents plus water. Not something you want to bring into contact with electronics. A friend of mine made this mistake, luckily she was simply trying to degrease an aluminum surface to use double sided tape for holding a power strip.

Here is a good source for electronic grade isopropyl alcohol:

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Mouser is the electronic component and electronic supply distributor that I use to source components and materials for most of my electronic engineering work. They have a great web site and wonderful customer service.

Another detail to keep in mind is never contaminate your bottle of isopropanol my using a swab more than once. Dip it in the bottle to moisten, use, and immediately discard. Dipping a second time into the bottle can potentially bring contaminates into the bottle hampering it's future usefulness.
 

Steaphany

Well-Known Member
There is a simple method to remove the effects of imager dust in post processing.

First, get and install
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. This program is freeware and yes it is intended for astronomical image post processing, but it can eliminate imager dust shadows.

Second, Get in the habit of shooting "flat frames". These are photos that you shoot of a uniformly lit featureless surface. There are many methods that are described on various web sites and in books covering the subject of astronomical photography, but the simplest method that I use is to photograph a pure cloudless smooth sky. Check your histogram to make sure your exposure is set correctly. If your shooting session does not permit a sky shot, then you can resort to the flat frame that you shot previously. To have the flat frame performance be at it's peak, make sure that the camera settings of file format and resolution match the photos. If you are out and use a number of lenses on a shoot, create a flat frame for each lens. With a zoom lens, it's not essential but do try to shoot a flat frame for each focal length that you use. In astronomical photography, your photo is commonly referred to as a "light frame".

In post processing, open the flat frame and drop the saturation down until you have a colorless monochrome uniformly grey image. Do not worry if your lens caused any vignetting where the corners are darker than the center. This process will compensate for that as well and vignette compensation was the primary driver for this aspect of astro photo processing. Save your monochrome flat frame. By eliminating the color, the flat frame will work uniformly across the complete color range of your light frame image.

DeepSkyStacker can work with multiple file formats, just not the Sigma X3F, so if you shoot RAW, I recommend that you save your flat frame and images as 16 bit TIF files.

In DeepSkyStacker, you will need to load only two files at a time. The image or light frame that you need to have imager dust removed from and your monochrome flat frame. DeepSkyStacker is more commonly used to process huge collections of files, but just loading these two will work fine. Then have DeepSkyStacker process the stack. Internally, DeepSkyStacker will adjust the lightness of the light frame by the variations recorded in the flat frame. A particle of dust on the imager will create a shadow in both images and the light frame is brightened to null out the effects of the dust. The output file from DeepSkyStacker can then be returned to your normal post process flow.

With flat frame compensation, you have no need to take any risks cleaning your imager for an occasional dust particle.
 

Steaphany

Well-Known Member
One of the prime sources of dust and particles which settle onto the imager is the shutter mechanism itself.

As with all mechanical systems, especially when new, the shutter mechanical components will wear and as they do, shed particles. The production and release of particles will diminish as the shutter settles in, but this phenomenon will never reach a level of zero. So, if you get a SD14, attach a lens, and never again open the camera body, you will still accumulate imager dust particles. The greatest accumulation being exactly while the SD14 is "brand new".

An advantage of the SD14 design is that Sigma redesigned the shutter mechanism from what they used is the SD9 and SD10 to achieve a greater than 100,000 exposures and to reduce the probability of dust particle creation and shedding.

Another source of dust is the lens mount. Here we have a mechanical metal against metal contact area with rubbing surfaces. Over time and as the mount breaks in, it too will wear and shed particles. An advantage of the SD14 design is the IR blocking filter will prevent the lens mount dust from reaching the imager. If your photographic style has you keeping with primarily a single lens, this will not effect you as badly as with someone who is constantly switching between lenses. If you read anything of basic dSLR care practices, the idea of storing your camera with a lens on is simply to reduce mount dust. The fewer over all lens changes. the better.

For times when you remove the IR blocking filter, whether to shoot IR, broad spectrum photography, or simply clean the imager surface, you are now at risk of allowing any accumulated mount dust to reach the imager. Always use a soft photographic brush to sweep out the majority of mount dust prior to removal of the IR blocking filter.
 

akv

Well-Known Member
Excellent info Steaphany thanks!
Here's a question for you, why do digital slr cameras need shutters in the first place? Wouldn't it be easier to just have the sensor act as it's own shutter? And you'd be able to achieve way faster "shutter" speeds than with any mechanical means, right?
Thanks again!
 

Steaphany

Well-Known Member
Mechanical shutters are not needed, but the choice of designing a camera with an electronic versus a mechanical shutter is up to a companies marketing and engineering teams.

For example, video cameras all employ electronic shutters. The reason being the nature of the images that the camera captures, video. Many specialty high speed and ultra high speed cameras use electronic shutters since a mechanical shutter can not respond fast enough. Cameras with live view or lacking a viewfinder requiring framing through the LCD screen use an electronic shutter or if they also have a mechanical shutter, it's kept open and only actuated during the actual exposure.

A feature of the Foveon imager employed by the SD14 but never implemented in the design by Sigma is the ability to capture video:

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So, think of the SD14 as having both an electronic shutter in the imager and a mechanical shutter.

Another aspect of relying solely on an electronic shutter is the imager is always being exposed to the light captured by the lens. If the Sun is within the field of view, then all that light is being focused onto very sensitive electronic elements. Have you ever used an magnifying glass to burn a leaf or piece of paper ? With in seconds, you get a nice plume of smoke. Just imagine that happening in your SD14 ? On another photography web site, I once read the panicked post from a photographer whose dSLR had literally gone up in smoke from Sun damage. I do not recall the model camera so I can not say what shutter design it used.

I remember watching the Moon landing coverage when an astronaut inadvertently aimed the live transmission video camera at the Sun. It lasted only a moment, but the camera was destroyed and useless. The remaining exploration of the Moon of that mission had no live video.

This does not mean that a mechanical shutter eliminates the risk of Sun damage, whether constructed of metal or plastic, focused Sun light can deform and damage a shutter, especially when the shutter is at the focal plane as in the SD14.

Another factor on choosing a shutter design is the philosophy behind the features and performance. If you ever visited Sigma's SD14 web site, they describe the SD14 as putting photographic control back into the hands of the photographer - as what was originally available in analog film based photography. I'm sure this contributed to their choice of employing a mechanical shutter.
 

jasonh

Well-Known Member
I'm not sure the exact reason for having a mechanical shutter any more honestly.

I've read many Nikons actually have a hybrid shutter. The shutter operates up to something like 1/150 or 1/250, and then the electronics take over. So the shutter is still going at 1/250 even when you are taking that 1/2000 shot. I know the SD14 doesn't do this, and I don't think many of the higher end Canons do either.

This is why on Nikons you can have a flash connected to the PC sync and take flash pics with stupidly high shutter speeds. On the SD and Canons you will get a portion of the frame unlit due to the shutter (1/250 is the fastest you can go on the SD14 btw)

edit: and what she said, haha.
 

akv

Well-Known Member
I never even thought about that! Foiled by the sun again! lol.
I'll keep thinking, I'm sure I'll find something to stump you with Steaphany...

Here's something nifty that I thought was very cool, since we're talking about shutters and Nikon.
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netzuser

Banned
Hi folks,
back to topic please.
Although it an interesting discussion on shutters, it´s off topic.
Please feel free to open another thread on shutters.
Regards
Uwe
 
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