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A77 and dust in sensor

Printed From: Dyxum.com
Category: Equipment forums
Forum Name: A-mount APS-C
Forum Description: For discussion of all Minolta and Sony a-mount APS-C cameras
URL: https://www.dyxum.com/dforum/forum_posts.asp?TID=133384
Printed Date: 15 December 2019 at 05:25


Topic: A77 and dust in sensor
Posted By: a77owner
Subject: A77 and dust in sensor
Date Posted: 21 October 2018 at 07:35
I have the A77 and i have the following problem.The dust in sensor.I cleaned it before 4 months,and now needs cleaning..I don't change lenses.I use the Tamron 70-300 usd only.I changed in my home 3 times the lens,but only in the home.Not outside.I can't pay too often 20 euros for cleaning.Do you have problem like this?I use the camera for planespotting
Sorry for my English!



Replies:
Posted By: SnowFella
Date Posted: 21 October 2018 at 08:08
Never read anything stating that the A77 is worse than any other SLT camera, dust is just one of those things that happen even if you keep one lens on or change all the time. Zoom lenses have a tendency to pump dust into the camera as they extend/contract so even keeping one lens on doesn't make it dust proof.

On a personal note though, my A77 is coming up on 100 000 shots and the sensor has never been wet cleaned. Nowadays it looks like I've sneezed into the mirror box if I stop down past F/9, biggest spots are still visible around F/5.6.
Haven't done an F/22 test in about a year but I suspect it would be ugly to say the least!


Posted By: Jozioau
Date Posted: 21 October 2018 at 08:32
At various times I have had reason to clean the sensors on my DSLT cameras (a99ii, a99 and a77ii). I use a 3 step process as necessary.
Firstly you go through the menus and select sensor cleaning mode and activate it.
Next carefully unclip the hold-down spring for the pellicle mirror, and then holding the camera face down, blow air across the sensor with a rocket blower.
Then refasten the pellicle mirror, re-attach a lens, stop down to f22 and take a shot of a clean background - a white wall or the sky, and check your image for dust bunnies.

If they are still visible, my next clean is done with a Visible Dust Arctic Butterfly charged fibreoptic brush.

If the spots are still there after testing, my last step is a wet clean using a drop or two of eclipse liquid onto a PecPad cloth wrapped onto a plastic sensor swipe.

All of these are readily viewable on YouTube.

If that's all too hard, then give it to a reputable camera service agency.

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"Your first 10,000 photographs are your worst" - Henri Cartier-Bresson
https://www.flickr.com/photos/jozioau/albums - My FlickrPro site


Posted By: a77owner
Date Posted: 21 October 2018 at 08:40
Thank you very much for the answer.
My camera has 46091 shots,and i gave it for cleaning in service about 10-12 times in 4 years...200 euros for cleaning...Too much i think...


Posted By: addy landzaat
Date Posted: 21 October 2018 at 08:47
Kalimera Your English is better then my Greek.

That is a lot of cleaning! And I hope that 200 price is a typo. You can clean it yourself, it is a little bit cheaper. Getting some dust at some point is unavoidable I guess, even if you do not change lenses. It might be the environment where you use your camera that plays a part. If it is dust, a small photographic blower might do the tric.

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Why not follow me on Instagram? @Addy_101


Posted By: a77owner
Date Posted: 21 October 2018 at 09:04
I pay 20 euros every time.Total for 10 times since 2014 200 euros!I will decide to buy a set for sensor cleaning.
Look how appears the sensor's dust in image.I did equalize a photo from yesterday spotting
1/600
F/9
ISO 100



Posted By: amrep
Date Posted: 21 October 2018 at 09:38
The spots in this photo are all the same size. It doesn't look like normal dust on the sensor. You need to investigate what is going on.


Posted By: SnowFella
Date Posted: 21 October 2018 at 10:09
Indeed look very large and strong to my eyes, how far in was it cropped and how much was it processed?
Here's one from just a few days ago out of my A77, 500mm lens, no crop and pushed in post to highlight the dust.

https://flic.kr/p/29v7wXN">
https://flic.kr/p/29v7wXN - Sensor dust by https://www.flickr.com/photos/153053144@N04/ - Johan Olsson , on Flickr


Posted By: a77owner
Date Posted: 21 October 2018 at 10:47
The subject,the airplane,is about 300m far from the shoot point.The picture is the original,i did only resize,no crop and withoun processed except the equalize.


Posted By: SnowFella
Date Posted: 21 October 2018 at 10:54
Looks like the spots would be about equal in size to mine then, maybe a tad more prominent from the equalize and slightly smaller aperture used.
I'm still living with cloning out mine in post but having serious thoughts about sending it in for a clean...local shop charges $90 for it.


Posted By: bartman
Date Posted: 21 October 2018 at 11:26
Because the spots are relatively large, maybe it's not de sensor causing this, but the lens. Start by cleaning the rear element with a blower and microfiber cloth.




Posted By: Phil Wood
Date Posted: 21 October 2018 at 11:34
Originally posted by SnowFella SnowFella wrote:

Looks like the spots would be about equal in size to mine then, maybe a tad more prominent from the equalize and slightly smaller aperture used.
I'm still living with cloning out mine in post but having serious thoughts about sending it in for a clean...local shop charges $90 for it.


That is pricey - you should start by trying to clean it yourself. As long as you are careful you will not damage it, the worst that will happen is that you make it dirtier, which will not increase the cost of a professional clean.

A 10x jeweller's loupe and torch (v cheap) or a sensor loupe (pricey) will help a lot, enabling you to see the dust you are trying to remove. The important thing is not to use much pressure and not to use anything that might scratch the coating on the sensor filter (which is what you are actually cleaning).

My cleaning regime:

Step 1. Use the A77 sensor clean function. This will shake off loose dust. I will usually do it with no lens mounted and the mirror flipped up and the camera facing down. The idea being that dislodged dust will fall out of the camera and not hang around to find the sensor again. TBH it doesn't usually do much for me, but it doesn't always fail.

Step 2. A blower - the stronger the better. I do use canned air if normal blowers don't work, some believe this can leave residue on the sensor, I have never seen this. Again, mirror flipped up, camera facing down. This will often dislodge dust.

Step 3. Dry wipe - I have tried Q-tips on their own, but find it difficult to get the contact point to coincide with the dust spot. I now use a clean lens cloth wrapped around one. This gets rid of most spots.

Step 4. Wet wipe. Tried this yesterday wrapping a wet lens wipe around a Q-tip and it worked a treat. I would have used the plastic sensor wipe thingy's I bought a month or so back, but couldn't find them when I needed them!

To see spots I take a picture of a featureless sky (if available) with the lens stopped down as far as possibly (f22, 32 etc) in close focus MF. This saves faffing about with PP. In the shot below there are plenty of dust spots, but the only one that appeared in normal shots was the big one at the top.



Posted By: stiuskr
Date Posted: 21 October 2018 at 12:04
That 20 euro per clean is a very good deal, especially when you see a shop wanting 90 to do the same thing but I suspect they're not doing the same thing and I don't think that 20 euros is buying you a full wet clean. If it does involve a wet clean then they're just going through the motions and not checking their work to see if the sensor is clean, i.e. spotless. You'd be better off spending that money on a rocket blower, a wet swab kit and in your case an inspection loupe as that's going to be a tough one to clean. Not all of the bits that stick to a sensor are dust, some of it is little metal flakes coming from the deteriorating coating on the shutter leaves and if those are left to sit in place they'll develop a static bond to the sensor and can't simply be blown away. Once you do get the sensor clean try and make it a habit of cleaning the sensor with a rocket blower after every session to get whatever dust was generated or ingested out of the camera before it settles.

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Rob Suits Jr.
a99M2 a99 a77 a700 KM7D|Min24/2.8 Min35/2 So50/1.4 So50/2.8 Min85/1.4G Tam90/2.8 Tam180/3.5|Tam17-50 CZ24-70G2 KM28-75D So70-200G1 So70-300G So70-400G1| SonyF60 AD200R2


Posted By: der dickgg
Date Posted: 21 October 2018 at 12:18
If you want to find out where the spots are take a picture without lens of an A4 paper moving the body a little with long exposure time. You'll see the dots!

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Quit a lot of ALPHA gear, a nice collection of Sigma lenses, Dynax and M42 stuff, NEX i.c.w. Sigma's, Gitzo's, Visico's and lots of video-equipment


Posted By: amrep
Date Posted: 21 October 2018 at 12:53
Looking at the pigeon picture and my own A77 photos the size of the spots seems to be typical for small point-like dust particles. (The size of the spots/shadows is related to the thickness of the sensor stack, including the AA filter "cover glass", but probably also to lens telecentricity.)

I usually has less than 5 such spots several months after a cleaning.

Some dust particles may come from the camera itself, especially the focal plane shutter. No matter how excellent they are made, metal parts are moving at high speed and cause slight grinding and dust. (If you think this sounds unlikely, take a close look at some door hinges in your home. Focal plane shutters are made of hinged metal blades.)

The bayonet mount and aperture mechanism also produce some dust.

All DSLR style cameras (including SLTs) needs sensor cleaning from time to time. A blower (rocket blower or rubber bulb syringe) is a first measure. But often there are some stubborn dust particles that won't go away, so you need to add a few tools. This is a very low cost alternative:
- Glasses, about +3 stronger than your normal. (Glasses may be easier to use than a magnifying glass/loupe.)
- A small pointed paintbrush.
- Lens cleaning tissue (very cheep on ebay).
- Some drops of clear alcohol (disinfection type mixture of about 70% with just ethanol and isopropyl works ok).

Wrap the tissue on the small paint brush and secure it (with tape or a twist tie). Point a spot lamp on the sensor. Wearing magnifying glasses you should now clearly see any major dust. Remember the image is projected upside down on the sensor. Dust spots near the top of a picture will come from dust near the bottom of the sensor. To make the dust stick to the cleaning tissue you can carefully breathe to let water condense on the sensor or moisture the tissue tip with a drop of alcohol. Change the tissue often (don't put dust back on the sensor).


Posted By: bartman
Date Posted: 21 October 2018 at 14:09
Originally posted by der dickgg der dickgg wrote:

If you want to find out where the spots are take a picture without lens of an A4 paper moving the body a little with long exposure time. You'll see the dots!




Posted By: eldonito
Date Posted: 29 November 2018 at 09:35
Γεια σου! If a blower won't do the job, I would recommend a good cleaning kit. It's scary, but following closely the instructions will do the job fine. And the more you do it, the better you will get at it. The cleaning kit should come with distilled water and sealed (one use) fiber-less brushes.

When I accidentally spat into my a77 sensor (eh, don't ask...), I used https://www.amazon.com/gp/product/B073WQ4699 - this kit successfully.

One thing to note for a77 (and other SLT cameras) is that the dust can also accumulate on the translucent mirror, so it may need cleaning too (both sides...). Just be very, very, very careful (as careful as you are with the sensor) because the mirror is actually a very thin and stretched membrane: it's very easy to warp or tear it! So apply as little pressure on the mirror as possible.

Good luck and all the best.

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https://www.flickr.com/photos/el_donito/ - my flickr


Posted By: genf
Date Posted: 29 November 2018 at 10:02
Originally posted by der dickgg der dickgg wrote:

If you want to find out where the spots are take a picture without lens of an A4 paper moving the body a little with long exposure time. You'll see the dots!


As an additional tip: use a very small aperture (f/16 or even smaller). That will make the spots even more prominent.

But be warned. It can look very bad this way.


Posted By: pegelli
Date Posted: 29 November 2018 at 10:08
http://www.dyxum.com/dforum/tp-cleaning-the-sensor-in-your-camera_topic31727.html - Here's a whole article on sensor cleaning from a few years ago

Still a very useful resource


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Mind the bandwidth of others, don't link pictures larger then 1024 wide or 960 pix high, http://www.dyxum.com/dforum/picture-size-for-posting_topic114856_post1379537.html#1379537 - see here



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