Twin Geeks Photography

If you’re here in Seattle – the sun’s out, the weather’s nice, and there are all these fun events going on. Time to go rent that cool lens and get some great pics, right?

Well, you’re not the only one thinking that. In fact, as the summer months kick off, rental houses enter into their busiest season.

Most rental houses, such as online folks like LensRentals.com, or local resources such as Glazer’s Camera Rentals – take reservations. And, if you you know you are going to be shooting an event, you should call in your rental reservations the moment you know the dates.  You can always cancel them if plans fall through.

In other words, don’t be like my sweetie, who forgot to call in her rental EF70-200mm f/2.8L IS for shooting the Fremont Solstice Parade today. Fortunately, this is a lens that I own, and I did find out after calling all around a 70-200mm f/2.8L (non Image-Stabalized) lens that I can rent. This event being important for her, I’ll be shooting my backup 40D and her backup 40D – and giving her my treasured “magic drain pipe”, my beloved EOS 5D Mk II and my 8Gb UDMA memory card.

As for me? I called in the rental EF400mm f/2.8L IS a year ago when Seafair’s dates were set…

Sensor dust. Chances are if you’ve shot DSLRs for a while, you’ve been bit by the problem – ugly black splotches on your images that you’ll have to clone out.

Once upon a time, when photographers still loaded and unloaded strange little metal cans into their cameras, nobody paid any real attention to changing lenses in the field. After all, you’d get a new sensor with each shot you take. Not true with DSLRs. Even worse, most imaging sensors carries some degree of static charge, making them a dust magnet when the mirror box is exposed during a lens change.

So, how do you check for sensor dust? This is my method:

* Mount a lens that supports a small aperture – say, f/22 or even better, f/32
* Pop the flash.
* Set your camera to Manual, sync speed, f/32 and use the ISO to adjust your exposure.
* Aim camera at white wall, then defocus the lens.
* Shoot a frame so that the exposure is just shy of clipping in the histogram.

Because the lens is defocused, the only thing that will be in focus in the image would be debris sitting on top of your sensor casting shadows onto the shot – the sensor dust that you’ll need to clean.