My Photo Blog

Lens Teleconverters

Teleconverters are one of those lens accessories that I have always had, but seldom used. They were for when there was no way you could get any closer to your subject. The common opinion was that they degraded image quality. In reality a well made teleconverter is not the problem, but that it is magnifying the flaws of the lens it’s attached to. The other drawback is the loss of lens speed. A 1.4x converter loses one f-stop, and a 2x converter loses two f-stops. For example if your lens is an f4 wide open, it will become an f8 when you add a 2x converter. The best ones are matched to the lens they are going to be used on and normally it’s a telephoto lens. What inspired me to write this blog, was that I was shooting products in which I always like to use a tilt shift lens. Like Goldie locks and the three bears, one lens was too long, and the other was too wide. The solution was to attach a 1.4x converter to my 24mm tilt shift lens turning it into a 34mm lens. I was amazed at how well it worked. Was it perfect, no, but my subject was in sharper focus than I could achieve with a standard lens. In doing a little research I found several photographers have tried this with good success. To go into a little more detail on the 24mm and 1.4x converter, lens tilts, and swings worked very well. Shifting lost a little sharpness, but no vignetting. Below is one of my test shots using the 24mm tilt shift lens with a 1.4x teleconverter. The lens aperture was f/8 and tilted 6 degrees. On the test shot below I did a 5mm shift and then merged the images in Photoshop. Next I tried a 2x converter, which turned my 24mm into a 48mm. Tilts and swings worked very well and the corners remained sharp. The one short coming with this combination is, it will not focus beyond 18 feet, but for tabletop product photography, it works very well. Below is an example with the lens set at f/8 and tilted 6 degrees. Please note that the f/8 setting on the lens is not the effective f/stop created by the teleconverters, which is f/16. .In conclusion, not all converters will work and you have to be careful that the rear lens element does not touch the converter’s element.

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