May 05, 2007

Dust on your sensor

I’m sure we’ve all had this happen…You take a photo, get back to your studio, download the photos to your computer, open them up and see in the sky’s the same black dot that show’s up over and over again. Reluctantly you open the file in Photoshop to rubber stamp out the dust.

To my dismay this happens more often than any of us like to admit. But unless you have kept the lens on the camera from the day you bought it, your going to attract dust to the sensor of your camera.

In the photo below, you can see in the sky specs that are not birds. I took the liberty to use red arrow's to point them out.

I find it impossible to even go out on a shoot and not change lenses at least once or twice. I use a TS-24mm often to shoot architecture and sometimes I don’t need that lens, but need to work with a lens with more flexibility in position where I can’t change my location. So I swap out the TS-24mm for my 24-105mm and get the shot. For a long time when I first bought my Canon 5d I left the 24-105mm on and dust still sneaks in though the lens. When you have lenses that move in and out to adjust for longer focal lengths, “dust happens”.

With camera’s that have larger image sensors (this can typically be tied to larger mega pixels) the ability to produce a magnetic reaction and attraction to dust skyrockets. So you’re frustrated and you pull off the lens and have a look. Below is a list of things you should never do:
1. Never blow (from your mouth) into your camera’s exposed mirror & sensor. Have you ever seen the shots when someone sneezes and a spray of crap comes out? Not much different, even if you blow gently.
2. Never use caned air to blow into your camera’s exposed mirror & sensor
3. Never leave your camera’s mirror and sensor exposed for longer than need be.
4. Never stick your fingers in to touch the mirror or sensor.
5. Never attempt to clean the mirror or sensor yourself by rubbing something on it.

Ok, so there is a list of things you can’t do. What can you do??
1. If you have a air bulb or something that can shoot air into your exposed mirror and sensor via squeezing with your hand is ok.
2. Wet a paper towel, expose the mirror & sensor, place the camera on a hard surface propped up a few inches for 10 minutes or more to allow dust to fall out and stick to the wet paper towel.
3. Try #1 & 2 with the mirror locked up and mirror down. You can find this in your camera’s manual, more than likely under custom functions.
4. Used canned Air on your Lens’s to clean them out. Always hold the caned air on a flat surface and move your lens around it rather than moving and tipping the can causing what looks like moisture to come out. This won’t happen if you keep the can on a flat surface.
5. Buy some E wipe’s (small wipes that attract dust and clean image surfaces) to keep your lens’s clean on the surface. Try to keep the barrels clean when fully extended. These things are dust traps.

What happens when you can’t remove the dust??
A few things can be done. If you live in Chicago you can take your camera to Calumet who in-turn sends the camera off to a guy named Tony Campos of TC Camera Repair. I know Tony from back in my LLFORD days as a sales Rep…so I just send it direct and save a few bucks. You won’t find anyone in Chicago willing to clean your camera or repair your camera that is insured as well as has been doing this type of service for years. Tony had a quick turn around and my only other option would be to send it to Canon. Canon would take weeks if not a month to work on my camera. Any way…options are out there. Don’t do it yourself unless you’re ready to pay close to 1k for any damage you do by sticking something you bought in a store that looks soft and end up scratching your sensor. Let a pro do it and if he makes a mistake…he pays for it…not you.

Posted by Robert R Gigliotti at 05:22 PM | Comments (0)

April 15, 2007

TS-E 24mm f/3.5L

The Canon Tilt Shift lens is a must have if you're a landscape or architecture photographer. One common problem that architecture photographers have is the subject matter often recedes or falls away from the view point creating an incorrect perspective. The TS-E 24mm can correct this issue and is useful for creating seamless wide-angle shots from two shots as well as capturing objects with great distances between them in focus. Other uses for the TS-E 24mm depend on how creative you want to get with your lens. But if you got one...you'll love it.

Wide angle shots
One of the very cool features of this lens is the ability to sift the lens +/- 11mm creating a 13mm wide angel shot when the two photos are stitched together. The only way to do this seamlessly is with a tripod. With a conventional lens you'd take a shot and move the camera a few degrees and take another shot. Even with a tripod, stitching the photos together you’d loose a considerable amount of data on the top and bottom due to bending when the two are brought together with software. This bending is because both photos must be warped to make them match up because of the movement when taking the photos from two different locations. With the TS-E the camera stays in place and the lens can shift giving you a full frame panoramic wide angle shot.

To show off this feature below is a photo I took from the Rookery building interior here in Chicago. It was designed by Frank Lloyd Wright. Click on the photo to see the full size version.

Perspective correcting
Taking photos of tall objects can be difficult with standard lenses. Sure, you can do it. I've been doing if for years and trying to fix the perspective in Photoshop. You can only do so much with Photoshop before you start to loose data and canvas size as well as quality of the photo. Who wants to spend time in Photoshop when the problem can be fixed at the source. Below is a photo I took with the TS-E 24mm with out shifting the lens.

This is a pretty low structure so I got down low so I would have to turn the camera lens from perpendicular to the line of the building to about a 45-degree angle upwards. This would represent a similar situation if I were taking a photo of a skyscraper from the ground. The turning of the lens is what creates this situation in the first place.

After shifting the lens while looking though the viewfinder I found an acceptable position where the building didn't seem to be receding into the distance and away from me. In order to take the photo in portrait I had to rotate the lens 90 degrees (the TS-E can rotate +/- 90 degrees) and turn the sift knob so the lens would shift up while keeping the lens nearly perpendicular to the structure’s main vertical line. The results are below.

Sometimes you need to take a photo that has an object with a reflective surface. Shifting can remove you or the camera to put that object in the center of the photo with out a reflection.

Tilting the lens
The tilting feature of the TS-E 24mm is +/- 8 degrees. This feature has the ability to take photos with great distances between objects with the entire focal plane in focus. An example may be a flower in the foreground and a building in the background. Tilting the lens towards the object keeping the camera body parallel to the image plane while manipulating focusing can achieve this.

With a shallower focal frame or with little depth you would normally only be able to keep all objects in focus, as no depth of fields is possible. The TS-E can create a shallow depth of field with manipulating the tilting feature and your relationship to the objects. What you can accomplish is only one object in focus with many other objects around the same object on the same focal plane.

Combining the tilting and shifting

When you bring both tilting and shifting together you can correctly control not only the perspective of the objects but keep them all in focus as well. This takes a bit of practice and trial and error. But with experience you'll create more control of your images.

Posted by Robert at 12:32 PM | Comments (0)