Sunday, August 27, 2006

Hartblei 45mm Super Rotator Lens

I've mentioned my Hartblei 45mm f/3.5 Super-Rotator Medium Format lens in a few previous posts. It is a truly unique lens and I've been meaning to write about it for a while.

I use it coupled with a Zork Panoramic Shift Adapter for Canon mount. The final part of the kit is a Really Right Stuff 'L' plate which has been modified to fit the adapter.

This combo allows simultaneous shift. 23mm in one direction with the adapter and a further 12mm in a perpendicular direction with the shift on the lens. I usually keep the shifts to 20mm (horizontal) and 10mm (vertical) respectively to maintain optiumum image quality. With these amounts of shift I can get an equivalent FOV to 24mm or wider on FF. Single row panos on 5D (2 shots) measure in at about 24Megapixels and 2x2 panos are about 48-50MP.

The Super rotator design also allows tilt on the lens in ANY direction. Very fun and very flexible. And sharp too!

How I make panoramas with this lens:

The lens is mounted so that the PSA is shifting side to side. That is the 'vertical' arm of the L-plate in the tripod clamp. The camera can rotate on the back of the adapter. I have the camera in horizontal orientation.

Most often I will just shift 20mm side to side to get a 3:1 panorama. I will take an extra picture at neutral point but the lateral shift images overlap anyway. The extra picture is just in case of moving elements or a critical subject which lies at the seams. This is extremely quick to set up and shoot and very easy to stitch in Photoshop. It's magic how easily the seams come together. No parallax whatsoever.

Of course, the lens is manual everything so it's best to set your focus and exposure before you start shifting and tilting. I first focus with the lens wide open. Then stop down to my chosen apperture. I will take a shot in Av mode to check metering and mentally record the shutter speed and check the histogram. The camera records apperture as 00. I then change to Manual mode and set the shutter speed (with minor adjustment depending on histogram) and also set a constant white balance - this ensures all images will have the same exposure and WB so stitching later is much easier. After this, it's time to start shifting and shooting.

It is also possible to do a huge 2x2 pano using this kit - the image at the top of the post is my most recent example using this technique. The procedure for a 2x2 pano is very similar to what I have described for a single row stitch above, except that you include some vertical shift on the lens as well.

So my shot procedure is as follows. Shift left 20mm on the PSA and up 10mm on the lens. Shoot. Slide across to central position - shoot - slide to 20mm right shift - shoot. Then press the shift direction release button and spin the lens 180 degrees. This will bring it from being shifted 10mm up to 10mm down. Shoot. Then slide back left to the central position on the adapter - shoot - slide to full 20mm left position - shoot. As I previously mentioned the central position images are not essential but can save a pano in certain situations.

Here is a demonstration of how the image panels overlap (each panel is 13 Megapixels)...

Check out the panorama links thread below for some other cool tutorials on flat stitching using shift lenses.

April 07. The lens is sold. I found it a bit bulky for my landscape kit. The lens was also prone to flare. It has been replaced with an Olympus 35 shift lens which is superb. Much smaller, better image quality, not as much shift and not tilt. I am using the oly for combined flat and rotational stitching.


Blogger /-\ \X/ |< | |\| said...

Very clever. I loveyour photography and hope to see more of it in the future.


8:50 pm, August 27, 2006  

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