GEAR REVIEW - DATACOLOR SPYDER LENSCAL
We all like our images to be sharp and in focus. There is probably nothing more annoying to us photographers than downloading your images onto the computer after a shoot and selecting the keepers, only to find upon opening the full res version that the focus has missed - sometimes by a country mile if you're shooting at very shallow depths of field.
If you experience this a lot, then it may be an indication of a problem. Possible causes could be bad technique, improper camera settings or in the worst case, a focus issue with the lens itself. Fortunately camera manufacturers have inbuilt micro-adjusting features to correct for the latter. Unfortunately, the fine tuning isn't available on all DSLRs, only some of the enthusiast level and upwards. If it's not on your camera, you're out of luck I'm afraid.
I recently purchased a Spyder Lenscal to calibrate my lenses with the D800. After removing the Lenscal from its packaging, I had a bit of a nightmare setting up. It comes "flat packed". The scale arm pictured above needs to be popped out from a small opening on the base. It took some jiggering about but eventually came free. I was a bit apprehensive about snapping it after spending £50, but with a sensible amount of pressure it will unclip.
Once assembled, I placed the Lenscal on a light stand with an adjustable head on it. This will enable you to level the Lenscal by way of the spirit bubble on the base. This can be a bit fiddly but its well worth taking the time to do. The more accurate you are, the better the end result will be.
The next step is to repeat the process with your camera. Mount this on a tripod at the same height as the center of the target. If your camera has an artificial horizon, use this to level everything. Once this is done you need to make sure the camera is square to target and also make sure you aren't within the minimum focus distance of the lens. If you have a long table or kitchen counter that is flat, then you could use it (although for some lenses this might not be feasible due to minimum focusing distance) but, as I didn't have one, the light stand/tripod combo was the only option.
For the easiest time of things, use a shutter release cable, remote control or timer. This makes the images much simpler to compare. You then take an exposure at the widest aperture. What we're looking for is "0" sharp in the center with the numbers either side the same amount in focus. This way you know that the lens is giving equal weight to the front and back. If the numbers in the foreground or background are clearly sharper, then you need to make some adjustments to correct this.
As it turned out, both my 50mm f/1.8D and 105mm Micro Nikkor were bang on the money and didn't require any adjustments. Way to go Nikon quality control! A friend was complaining he'd recently done a shoot and the focus had missed on pretty much every shot with his Tamron 24-70 f/2.8 VC. He brought all his lenses into the studio - many of which are third party and we began testing. Nearly all required some fairly major fine tuning as all were suffering front focus problems
After almost an hour calibrating each lens, we tested them on random objects. The results were nice and sharp and lenses nailing focus every time. While you could do the same test with pretty much any object that has lots of contrast in it, the Lenscal takes it to the next level and allows you to get extremely high accuracy for when focus is critical, as in portraits with very shallow depths of field.
One thing worth pointing out is that the Canon 5DMKIII is currently the only camera body capable of micro adjusting zoom lenses. IE it allows you to enter two values. One for the wide end and the other for telephoto. So if you have a prime lens you can correct that no problem but, if your zoom has a focus issue, then you're chasing your tail unless you have the Canon. Hopefully Nikon can address this in a firmware update.
Would I recommend the Lenscal? Answer, yes. Although £50 seems a lot when you consider there's really not a great deal to the product itself, the real value comes from what it helps you achieve. If you've just sunk £500 - £1500 on some professional glass, you want it nailing focus. The Datacolor Lenscal will help you identify and correct focus issues quickly and easily.