Monday, 7 April 2014

Trying a new idea - sealing the optical chamber on the DSLR

Every now and then a product comes along that looks genuinely interesting. One such is the Dust-Shield from Dust-Aid. This interesting product is remarkably like the protective sheet you use on your phone screen.


This is the Dust-Shield within its protective packaging. The round clear bit in the middle is the protective shield. It's shaped to fit my 5D/II without interfering with the lens or its electrical connections. I suspect that it might be a little challenged with APS-C lenses because they protrude further into the body.

Before fitting the camera, and even though my sensor was fairly clean I decided to go the whole hog and clean the body outside and in.

First up I used a cheap micro fibre cloth from the hardware store to dry wipe the entire body getting into as many nooks and crannies as I could.

These cloths are great, they pick up loads of dirt and don't drop much lint.

You can even wash them. You can tell when they're dirty because they stop grabbing you.

There are always one or two of these in my camera bag.


Next up I cleaned the eye piece with a swab with a couple of drops of sensor cleaner on it.

This removed the last few months of dirt.

One of the down sides of using the Black Rapid strap instead of a traditional strap is that the back of the camera is exposed more to grub.

It does have an up side though, since the camera is suspended upside down the upper controls stay fairly clean.

After working on the important bit I used the same swab to get into all the grubby beats around the outside of the body.


Now onto the optical chamber.

Firstly I found and carefully picked out a hair that's been giving me the shits for a while out of the mirror assembly.

Most of the time it was only visible while sighting but every now and then it found its way onto the sensor and into images.

This image shows the optical chamber with the mirror in its normal position reflecting light up through the prism into the eyepiece.

The mirror directs light to your eye while sighting then flips up and out of the way when you shoot an image.

The reasons the mirror can shake the camera is all that moving mass.

To access the rest of the chamber and the sensor itself, well ok, the glass filter over the top of the sensor place the camera into sensor cleaning mode which will flip the mirror up and keep it there until you turn off the camera.

Don't leave it like this too long as you risk burning out the solenoid that holds the mirror up. Minutes at a time won't hurt anyone but don't forget it and leave it like this.

Besides the longer its like this the more dust will settle on the sensor.


Before hitting the sensor with a wet clean I had another quick go with the silicone based Dust-Wand. This uses the principal of the silicone block being "sticky" to dust without actually being sticky.

Before you use it, you clean it on one the plastic strips that come for the purpose. It's very important to not touch the silicone or the cleaning strip as you'll end up with oil on your sensor.

The wand is pretty simple you press it down gently but firmly onto the sensor at 90 degrees (want straight up) and it picks up the loose dust.

Its a good idea to do this (or at least blow) before a wet clean to get off anything loose that might scratch your sensor.



Of course keeping the chamber open while I took these images meant I was dropping in more dust than I was taking out.

There is a staggering amount of dust in the air, even if the room is clean there is still loads of it.







In preparing for the wet clean I wrapped the wand (not the same one as the dry!!) in the supplied cloth and wet it with the sensor cleaning solution.

I found that I needed to use a little more than the five drops recommend because this stuff evaporates really quickly.






Swiping in one direction using the wet swab. This is as always a bit of a painful process but after a few repeats changing sides and cloths with new fluid you do get there.

This fluid from Dust-Aid was much better than the fluid I used last time as it didn't leave any streaks.

I'm quite pleased with the result. I've still got one spot but even I'm not that fussy or crazy enough for another go.

After checking (remember to clean the back of your lens before you put it on) it was time to move onto the protective sheet where this whole journey began.


This instructions made no sense to me at all, so I just did it :).

You start by removing the protective backing sheet using the plastic tabs to hold onto the shield without leaving finger marks on it.





Once the backing sheet is off, the shield is positioned in the chamber using the alignment marks and tabs.

There is adhesive that helps the sheet adhere to the camera body.

Take care in positioning the shield that you don't prevent the lens electrical connections from working and don't interfere with the flange that locks the lens in place.


Once the shield is in place it just about disappears. It will be very interesting as I experiment over the coming days in different lighting conditions and lenses to see if the shield alters the image in a way that can be perceived. I know my machine pretty well and will be able to determine reasonably objectively  by comparing similar images from the same lens from my catalogue over recent times. I did get one spot of dust on the back that I didn't notice before it was in. Oh well... The good news is when dust settles on the outside you just blow it off with a rocket blower. If this thing works I'll be bloody impressed. 

Update - The device has been in for a week.

Well it's time to do the first update to this post. We've had a shocking week weather wise and I've been unable to test for sun flaring or other impacts. However, I have learned that at ISO 2000 that my machine would normally handle in its stride in low light with a pin sharp lens the device seems to introduce an effect remarkably like film grain.

You can see the effect I'm discussing in this image. Especially in the girls faces. In the full size image you can't see it, but zoomed in as I am here with a crop of around 1/8th of the sensor area it certainly becomes apparent. Update: I tried this scenario again with two 5d bodies, one with and one without dust-shield with the same lens and the problem is the 5d not dust-shield.

I'm very pleased to report that in good light there are no issues with the images shot through the device.

This image is the same crop from the sensor area as the girls in the rain image. This is shot at f/5.6 at ISO 500 with flash for illumination using the 100mm prime macro lens. It has the sharpness and image attributes I'm used to from this lens


This image is an extreme example at 1:1 pixel for pixel from an image taken using the same settings and lens as the cat face above. This image also demonstrates the sharpness I'm used to and there is no apparent change from the Dust-Shield.

Update

I've been using the Dust Shield for a month and a half now including my full gamut of image taking places, lights and styles. Including my last Great Ocean Road image gathering road trip. It does not seem to make any difference to image quality except there is some additional subtle flaring when taking images into the sun, personally I like the flaring so this doesn't worry me at all. For some example images read on to my Great Ocean Road blog post. All of the images in that post were taken through the Dust Shield. 

Better yet the dust that gathers on the outside of the Dust Shield just get blown off with the blower. I've had no dust on the sensor at all. It's just so much better not having to remove dust spots from my images. The only downside and it's minor is that the material is soft and will scratch over time but is easy to replace and is affordable. There just don't seem to be any real negatives to using this product and I certainly won't be removing it from the camera until it's time to replace it.