Tuesday, July 6, 2010

Micro AF Adjustment

The one gimmick that came out with the newest Canon DSLR models (50D, 7D, 5D II, 1D III, 1Ds III, and 1D IV) that really made me want to upgrade is the Micro AF Adjustment (MAA) ability. Basically what it does is allow you to calibrate the lens to achieve perfect focus without having to send the body and lens to Canon Service Center. Sometimes the perceived "softness" of a lens can be attributed to an uncalibrated lens causing back-focusing or front-focusing. This feature allows you to calibrate any one type of lens to the body.

In order to aid MAA, there is a product called LensAlign Pro Focus Calibration System with Enumerator (US$179.95) which makes it easy and fast. This is what the product looks like:

My friend Methodical at POTN gave a nice recipe on how to use this apparatus with MAA.

Method for all test shots:

- Av mode
- Widest aperture
- ISO 400-1600
- Cable release
- In camera 2 second timer
- LensAlign Ruler

First off I’d suggest, as suggested by Michael Tapes, that you use a tripod to mount the LensAlign as it takes the task much simpler to align the target. The kit comes with the standard ruler for the shorter focal length lens and the longer ruler (4’) for the longer lens.

Canon 85 1.8 and 50D: This is the initial shot before going into editor. You can see what it looks like before any analytical work is done.

This time I did not use Paul Westphal’s suggestion of 50x the lens focal length. I used the 25x the lens focal length and various ISO settings, which cut my working distances in half (see above). This allowed me to work out of my garage (camera and lens in garage, LensAlign in driveway). The working distance (camera setup) from my garage to the end of the apron is about 84’ – perfect for my working distance.

Same shot as above except I used photoshop emboss filter to highlight the focal point on the ruler. You can clearly see that the lens is back focusing.

I set up the tripod with the LensAlign and back sighted the bulls eye to the lens. This is an easy step – just look through the bulls eye hole back to the lens and center. At this point, you are about 95% on target. I then go back to the camera and lens in the garage (out of the sun) and put the camera in live view mode, zoom in to 10x to check the alignment with the bulls eye and make adjustment at the camera end if necessary. Once aligned, I shut off live view and adjust camera and lens, via the view finder, so that the focus point is centered on the bulls eye (you will need to enable focus point so that it is visible in the viewfinder). I then lock things down, check to make sure all the settings are correct, defocus the lens and take 3 base shots, defocusing each time and waiting for things to settle down, especially with the long focal length lens. I download and open those photos in PSE7 and take them to the Editor. In Editor, I emboss each photo (find edge filter is useful too), and do an auto sharpen if necessary, and use various zooms (i.e. 50, 100% etc.) to analyze where the focus falls on the ruler (front, back or spot on). If, for example the lens front focused, I go back and take 2 test shots each using various MAA dialed in, say, in this example +3, 5, 7, 9 etc.). I download and open in PSE7, take them to Editor and perform the same steps as above. Once I determine which adjustment centers the focus on the ruler, I dial it in the camera, save all files for future use, and created a spreadsheet with the before and after LensAlign MAA – this is personal so that I can compare the MAA between methods. After testing a few lenses, I kind of got a good feel for what MAA to use to make additional test shots to get things closer. Btw, I tested a couple lenses with the MAA from my old method using the LensAlign and some were way off.

Here's one of the test shots with a - 4 micro af adjusment, which put focus to the center - on "0" (i.e. corrected the back focusing issue)

Again, I faced 2 uncontrollable variables, light and wind, but this time consistent light was not really a major concern as it was when using my old method to perform the MAA because the ruler will show the results no matter what as long as you have some light on it. So my major enemy was wind. A couple times it knocked the large ruler out of place so the remedy was to set it in place and use some tape (painters) to keep it in place (place under the ruler of course). It would be good if you have a large indoor place to do the test for the longer lens. My method for the wind enemy was patience. I just waited till the wind stopped.

Wednesday, June 30, 2010

Shutter Count

Ever wanted to know how many shutter actuations your camera has? There is a Perl script called ExifTool which extracts a whole bunch of useful information from your images. You need to run the script in a terminal shell. Here is an example:

macbookair$ exiftool MD7D5952.CR2 | grep "Shutter Count"
Shutter Count : 414023

Simple enough right? Enjoy!

Friday, June 25, 2010

Keep your gear nice and dry!

For photographers living in humid environments, keeping your gear away from moisture is very important. Mold, fungus, and other nasty stuff can ruin your lenses very quickly. Ideally you want room temperature, occasional direct sunlight, and humidity within 20% and 60%. Anything lower or higher than that will cause fungus growth. The same can be said about our gear bags. To aid in humidity control, silica gel bags can do miracles. One such supplier here in Brazil is Didai Technologia Ltda. It is also important to air out those lenses that don't see much action. Take them out once every week so that it can also get some much needed sunlight. Below is my custom-made all-glass cabinet where I keep all my camera gear. Notice the temperature and humidity indicator device in the middle of the cabinet.

Friday, June 11, 2010

Service Notice: EOS 5D: Main Mirror Detachment

Thank you for using Canon products.

We have discovered that, in rare instances, the main mirror of some EOS 5D Digital SLR cameras may detach due to deterioration in the strength of the adhesive. Accordingly, we would like to convey the details and our service policy concerning this phenomenon.

We offer our sincerest apologies to those customers who have been inconvenienced by this issue. Canon always strives to provide the highest quality products to our customers and we will spare no effort in our quality management to make sure our customers can use our products with confidence. We hope our efforts will earn your understanding.

The main mirror of the camera detaches and images cannot be viewed through the viewfinder.

Affected products
EOS 5D Digital SLR cameras whose main mirror has detached.

User Support
We will repair and reinforce the mirror portion of the affected products free of charge. If you own one of the affected products, please contact our Customer Support Center.

We appreciate your patience, and we offer our sincerest apologies to the customers using these products who have been inconvenienced by this issue.

This information is for residents of the United States and Puerto Rico only. If you do not reside in the USA or Puerto Rico, please contact the Canon Customer Support Center in your region.

Contact Information for Inquiries
Canon U.S.A., Inc.
Customer Support Center
Phone: 1-800-OK-CANON (toll free)
Email: carecenter@cits.canon.com
Support options and hours of operation: www.canontechsupport.com

Before Fix:

After Fix: Notice the thin metal strip added to the mirror "holder arm" (both sides)

DSLR Sensor Cleaning

Have you ever noticed some dark tiny spots on your images? Did you happen to notice that they appear in the same exact spot image after image? If so, then you've just witnessed your first "sensor booger" as they are affectionately called. Put simply, they are just dust/dirt particles that landed on the camera's sensor low-pass filter. Cleaning the sensor (actually the low-pass filter over the actual sensor) can look like a daunting task, but with enough knowledge, some hand coordination, and a little bit of hands-on do-it-yourself spirit, anyone can perform this operation with little risk. Since a picture is worth a thousand words, let me show you a video instead:

Tuesday, May 4, 2010

1D4: Need For Speed

Look what I found at Canon's CPN website:

"EOS-1D Mark IV – Faster shutter speed needs

As the resolution of cameras increases, and pixel sizes decrease, you may find that there is a need to use faster shutter speeds. The smaller pixels in cameras mean that any slight subject movement during the exposure is more likely to show up as subject blur – this is because it doesn’t have to move as far to affect more pixels. To avoid this just use a faster shutter speed than you would previously have done. For example, if you previously used 1/500sec, you could now try using 1/1000sec or faster."

How many of you knew about this? This may be one reason why some of your images do not look tack sharp at 100% view. The other reasons are severe case of epilepsy or a mis-aligned lens requiring focus micro-adjustment. This is just a Canon disclaimer to avoid thousands of complaints from pixel-peepers like us!