DIY sensor cleaning tutorial


Note: this article is a translation from French of the excellent article
written by Stéphane on his Folo blog. There are already a few articles on this topic on the net but Stéphane post is well illustrated and simple.

Of course, cleaning your camera sensor can be a dangerous operation and I cant be responsible of the result. Do it at your own risk.

Start of article

This tutorial will show you a simple, safe and cheap way to clean your DSLR sensor. The technique shown here is much safer than some others, reliable and used by the author plus many other pro photographers. Of course, there are no warranty of success since a bad execution of the procedure could result in damage to the camera.

If you take your time and do it in a relaxed mindset, you should be fine. You can also ask a professional to do it in case you are scared. The advantage of doing it yourself is that you can clean your sensor outside of normal business hours, just before an important shoot.

Before starting with the procedure, lets make something clear: we are using the term ‘sensor cleaning’ but in fact we are not cleaning the sensor it self, we are cleaning the protective filter which is on top of the sensor.

Note from Alain: If you ever happen to damage the filter, it cost about 400$ to replace according to the repair center I have contacted.

What you will need:

capteurclean-009-3

[Read more...]

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5DMrkII vs D3 exposure differences?

Edit: I was stupid! Explanation here.

Last week I went shooting with my friend Christopher who is a D3 owner. It was more of a scouting trip, to find nice locations in downtown Montreal ,for future shoot than anything else. To make a long story short, we ended up doing some tests/comparison between our two cameras. Frustratingly enough, Chris managed to do a shot that I was failing to get. Wanting to get the same picture at a real man resolution (21>12), I dialed the same settings on my 5DMrkII and took the shot, expecting the same results.

Oh boy, I was in for a surprise! Glancing at my LCD I clearly saw that my image was different than his (mine was darker). It could have been and LCD brightness setting so we compared histograms. Technically, if we both shot at same ISO, shutter speed & aperture, the amount of light burning the sensor should be the same, resulting in the same image/histogram. Unfortunately, it was not the case! How comes?

I was about to post the two shots but unfortunately, it seems like I deleted mine (probably out of frustration!). Dont fear, I still have a valid example. The darkest image (left) is from my 5D @f4,5 for 1/60 and the other (right) is from the D3 @f4,5 for 1/100, both at ISO800, @70mm and were taken minutes apart. Even with 2/3 more light (1/60 vs 1/100) the 5D picture is still much darker, and at full resolution much noisier so imagine how the 1/100sec one was!

Anyone has an explanation?

img_1207dsc_3122

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Hot Pixels in video mode!!!

The issue

At first, I thought it was dust. Dust on the sensor or on the lens. Then, after watching every single video I shot since I got the camera, I saw something worst than the black dot problem: hot pixels! And to make things worst, there are 2 of them!

I did not notice them at first because most of my shots were done in bright light but last weekend I had to shoot some video for the CD launch of my friend Jon Davis (f1.4 ISO3200, hence the noise…) and the white dots on the dark background cant be missed.

This is a rare but not unknown issue.Bbut it seems like there is some confusion between people having serious noise issues while taking long low light pictures (a problem I am not having) and the problem I am having with videos. My problem is not noise, it really is white (hot) pixels. Take a look at the screen capture:

full

Click to enlarge

You can see a 100% crop of the problematic area here:

detail

While it is not very noticeable on still images, as soon as the camera starts panning it jumps off the screen and destroy the whole scene. You can see it in the home made clip I did last week too.

What I have tried so far

First, I used the manual auto-cleaning feature about 10 times in a row to see if it could “unstuck” the pixel without success. Then I updated the firmware to 1.07 and they are still there.

My last resort was to call the store. They were very helpful. I will have to bring my camera back Friday and they will see if they can trade mine for a new one straight or, at worst, send it for repair (urck!). If they send it for repair I will try to get an “equivalent” camera until I have my replacement. By equivalent I am of course thinking about these Hasselblad that no body ever rents!

I will report back on this Friday.

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Is 21 megapixels enough?

After reading the article How many megapixels are enough at the digital photography school and reading the comments, I felt compelled to make a post about it. After all, as the owner of both a 5DMrkII and this website, I have to have an opinion on the subject!

Why megapixels are important?

When you talk about megapixel count, most people think about maximum print size. While this is true, there is more to it than that, especially since so few people print anymore. 

First, the more pixels you have to play with, the more flexibility you have in your cropping choices. For example, it is almost possible to fit a portrait picture taken from the original 5d in a Canon 5DMrkII landscape picture! This very useful when you are not sure about the perfect crop for a shot or simply when you realize that a shot is more interesting with an alternative crop. Or you can even just point the camera in a general direction, take a picture then crop it afterward, paparazzi style.

The next big advantage might be a bit less obvious to most people: post processing treatment. The premise is simple: the more pixel you have in a picture, the smoother curves and gradations can be. It is the same with sharpening. This is why fashion photographers use medium format camera: they want their negatives to be as big as possible so their retoucher could more easily smooth the skin and sharpen the eyes/hair. If you dont trust me, resize one of your picture to 800×1200 and apply the same post processing tasks as you did on the original and see the difference. See? More megapixel is better for post processing!

Finally, when you down sample a picture, it tends to sharpen it, so the bigger the original picture, the sharper it can get when you output it at a lesser size. 

Limitations

Camera manufacturers are facing a problem: the lens they are selling are not able to support the high photo-sites count of the newest breed of sensors. Basically, no matter the megapixel count of the sensor, lenses have reached their maximum performance. While it is possible to create higher quality glass, it would not be very practical since only a subset of the market would buy them which would’nt make the operation cost effective. 

That is why I think camera manufacturers are going to stop the megapixel race at about the current level and move toward noise management. 

Conclusion

While megapixels are important, ISO is also a key factor in picture quality and the debate regarding the importance of ISO vs megapixel count has more to do with shooting style than general guideline. But even then, the 5DMrkII has some very good low light performance so there is not much to worry about…

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