Sensor dust - something to be worried about?

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ChrisRaper
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Sensor dust - something to be worried about?

Post by ChrisRaper »

I am new to the forum - first post so be gentle ;)

I have just bought my first dSLR (a Canon-refurbished 1000D) for a pet project to obtain stacked photos of all the UK tachinid species. I have done a quick sensor dust check (a photo of a cloud at f32 etc.) and found that the camera has a few specs on the sensor but no scratches or swirls from bad cleaning.

What I was wondering is - should I be worried and should I return the camera or is sensor dust just a fact of life and I should get on with using the camera until the dust becomes too much of a problem to PhotoShop out - and then clean it myself? :)

Are there any good threads on the forum that describe the best methods to clean sensors ... or do people send their cameras off for professional cleaning these days?

Thanks! :)

ChrisLilley
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Post by ChrisLilley »

Hi

First, welcome to the forum.

Second, be gentle for the non-experts, what is a tachinid exactly?

Thirdly, sensor dust. A few spots are to be expected on any SLR as the inevitable result of changing lenses. They are in general nothing to worry about. SLRs which feature sensor cleaning can clean themselves; ones that don't can be cleaned by removing the lens, holding the camera mount-downwards (so the dust can fall out rather than collect in the mirror housing) and using a blower.

As long as it is dust and not some sort of sticky particulate, this method will suffice and will not risk damaging the sensor (actually, the protective glass, anti-aliasing and IR-blocking filter; the sensor is behind all that).

Photoshopping out the diust is another option, but becomes difficult if the affected area has a lot of detail and becomes tedious to do for a hundred or so images (such as you would use when stacking photos).

SONYNUT
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Post by SONYNUT »

Get a squeeze type blower...remove what you can..if its still a problem most camera stores can clean it for you...for a price....on thing about film..you always had a fresh sensor.. :wink:
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Charles Krebs
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Post by Charles Krebs »

Unless you live in a cleanroom (and maybe even then... as some of the "dust" will be generated from inside the camera), it is a fact of life.

Small effective apertures makes any dust more noticeable. And stacking can create "trails" as the dust is seen as a detail and picked up and repeated by the software.
or is sensor dust just a fact of life and I should get on with using the camera until the dust becomes too much of a problem to PhotoShop out - and then clean it myself?
That's the most rational approach. Naturally be as cautious as possible about dust "cleanliness"... changing lenses, body caps, lens rear caps and such. You will probably want to learn to clean it yourself. I'm of the opinion that it is hard to adequately clean a sensor for microscope or very high magnification "macro" without being able to observe the sensor while cleaning. I use a small, low power stereo microscope with good working distance, but there are a few magnifying products made for sensor cleaning (and no reason a nice big old magnifying glass could not be made to work OK for this use.)

NikonUser
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Post by NikonUser »

Welcome Chris. I 'know' you (computer-wise) from Diptera.info and your blogs.
For the relatively low magnifications you need for tachinids you should not see any dust spots on the final images.
If you see dust spots at 10x or below then you really have a dirty sensor and it should be cleaned.
My dust spots don't pose a problem until I get to 40x and above.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

ChrisRaper
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Post by ChrisRaper »

Thanks everyone ... I have one of those squeezy blowers on order so I will give that a try and just see how it goes. :)

I started worrying over the fact that the new camera had dust but then when I checked other friend's stacks that they have done for me they all had dust streaks so I decided it was better to be pragmatic about it. A new camera might start of with or without dust but the only thing we can be sure of is that it will always get more dust as time goes on and will eventually need cleaning. I just need to manage as clean an environment as possible when changing lenses:
- always power off when changing lenses
- expose the sensor for the minimum possible time
- make sure that bellows, tubes & lenses are dust free
etc.

Out of interest, does anyone think those in-camera sensor cleaning procedures actually works? What do you think of the Dust Delete Data system in the Canons?

ChrisRaper
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Post by ChrisRaper »

NikonUser wrote:Welcome Chris. I 'know' you (computer-wise) from Diptera.info and your blogs.
For the relatively low magnifications you need for tachinids you should not see any dust spots on the final images.
If you see dust spots at 10x or below then you really have a dirty sensor and it should be cleaned.
My dust spots don't pose a problem until I get to 40x and above.
Hi NU - thanks for the advice - much appreciated :) Funny how many friends crop up on other forums! ;)

SONYNUT
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Post by SONYNUT »

Some spots are not dust....In the summer I get dried condensation from going out from AC ect...sucks :roll:
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ChrisRaper
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Post by ChrisRaper »

ChrisLilley wrote:Second, be gentle for the non-experts, what is a tachinid exactly?
Hi Chris - tachinids are a fascinating group of flies (family Tachinidae) whose larvae are parasitoids of the larvae of other insects, such as butterflies, moths & beetles. Their larvae eventually kill the host - a bit like in the Alien movies! ;) I run the UK recording scheme with a friend and one of my responsibilities is to look after our website (http://tachinidae.org.uk/) and I have set myself a task of providing high-quality photographs of every UK species (270+) with detailed close-ups of the body parts that are used in the keys. It's a huge project and I've got a lot to learn but this seems a really friendly forum so I'm in the right place :)

ChrisR
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Post by ChrisR »

Hi Chris, nice to see you over here :)
Have a look at this thread, there are some images on the third page which make your sensor look pretty clean:
here .

ChrisRaper
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Post by ChrisRaper »

I see what you mean ... I think I will just use mine and see what the end results are like. If the sensor needs cleaning then I'll cross that bridge when I get to it but I will put it down to "all part of the learning exercise" because it looks like we all have to learn how to clean them at some point or other! ;)

I'm still a bit confused as to the effectiveness of the Canon sensor cleaning procedures ... and the Dust Delete Data function. Are they worth engaging or are they really just a gimmick?

Craig Gerard
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Post by Craig Gerard »

Chris,

The mechanical sensor cleaning capabilities in current DSLRs are improving and do provide a useful function; but I do not believe such an approach has developed sufficiently to date.

The Dust Delete Data Function (DDDF).....I've never used it, I deal with the dust manually in post-production. In practice, the DDDF targets an area or areas of an image and the Canon software, in post-production, rubs-out the dust by blending in the data of surrounding pixels. The DDDF works in unison with the Canon EOS software...if you use Canon's software for post-production (it is very good software); otherwise, as in my case, it offers no advantages.

If you are intending to use PhaseOne CP1, DxO Optics, Adobe Lightroom, Apple Aperture, Bibble, etc, for post-production, as far I know, the Dust Delete Data Function will be of no benefit.

In most of the programs listed above you can apply dust correction to one image, select a bunch of additional images and 'apply' or 'sync' the correction to the selected 'batch' with a couple of clicks; the same as if 'applying' any other adjustment to a batch. All images in a focus-stack sequence could be described as a 'batch'.



Craig
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ChrisRaper
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Post by ChrisRaper »

Thanks Craig - that sounds logical. It did mention that the system writes data into the JPGs so I suppose, like you say, it needs their software to do the post-proc. I usually just take the photos, stack with Zerene and then just deal with dust streaks in PhotoShop. My finished output only has to be a maximum of 1920x1080p resolution for web use anyway so even my ham-fisted touch-ups aren't usually noticeable ;)

NikonUser
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Post by NikonUser »

Chris: I just uploaded an image that shows a few dust spots on my sensor,
but only at actual pixel level at 100x mag
HERE
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

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