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Using a Teleconverter with a TS-E lens

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Teleconverter use with a TS-E tilt/shift lens

Altering the focal length of a tilt & shift lens by 1.4x or 2x


Changing focal length for TS-E lenses with a teleconverter

A quick test using the Canon EF 2x Converter (Teleconverter) with the TS-E 17mm f4L tilt shift lens.

The 2x teleconverter is my concession to rarely needing a long lens when I’m out and about. I’ve got it in the bag for attaching to my 70-200 2.8L IS to get an equivalent 400/5.6 IS lens. If I needed a 400 mm lens for the type of work I do then I’d get one, but as yet I’ve not come up with a good enough business reason…

I’ve heard people ask if the 17mm TS-E lens and 1.4 TC would be good enough to just buy the 17mm, rather than the 24mm. Note that 17×1.4 conveniently comes out at ~24mm.

1Ds3 with TS-E 17mm and EF2x teleconverter

1Ds3 with TS-E 17mm and EF2x teleconverter

To see the impact of the TC, which always lowers quality to some extent. I did a quick test in the street outside.

Here’s three shots (@f/11) using the 17mm, shifted 12mm either way.

17mm no shift

17mm no shift

 

17mm full left shift (12mm)

17mm full left shift (12mm)

 

17mm full right shift (12mm)

17mm full right shift (12mm)

A detail of the LH edge.

17mm full shift 100% crop

17mm full shift 100% crop

Sharp and with minimal CA

Let’s see the results at 34mm (17mm x2). These are with a lens setting of f/5.6 to get f/11 with the 2x TC

17mm x2 no shift

17mm x2 no shift

 

17mm x2 right shift

17mm x2 right shift

 

17mm x2 left shift

17mm x2 left shift

A detail shows softness and CA

100% crop full shift 34mm

100% crop full shift 34mm

By using the canvas extension technique I described in my original tilt/shift lens article, I was able to use the lens correction filter in Photoshop to fix the basic CA (not actually that much)

This is the ‘fixed’ version, after a little sharpening with the CA fix

After fixing some Chromatic Aberration and softness

After fixing some Chromatic Aberration and softness

This is at the extreme edge of the field, with some residual CA after fixing it to look best in the rest of the image.

I extended the canvas by 233% rightwards to place the middle of the image along the lens axis.

Here’s a combination of images from the ’34mm’ set-up, showing how the shift (12mm) looks.

shifted images at 34mm focal length

shifted images at 34mm focal length

So, is it of any use?

The fact that I have to use the lens at f/5.6 to get f/11 equivalent is a major cause of softening of the image, along with the extra glass in the optical path.

I could use f/8, to get f/16 (equivalent with 2x TC), but at f/16 I’m potentially getting diffraction softening of the image (with a 21MP FF sensor)

I did try some other settings and found that the image was a tad better at a lens setting of f/8, but not really enough to show here. I’ve not got a 1.4x TC, but I’d expect the results to be somewhat better and potentially usable if you can’t justify the 17 and 24mm.

I now know that with modest shift, I now have 34mm available as a T/S lens, although I suspect that I’d just use the 24mm and crop ;-)

No doubt, as the 17mm ships more widely, we’ll see some detailed comparisons, but I thought I’d give it a go…

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