Selasa, 18 Juni 2013

Using the Voigtlander 12mm and 15mm lenses on the Leica M (240)

I use my Leica mostly for travel and landscape photography and like having very wide angle lenses available for dramatic, sweeping effects tying in the foreground and background. My widest Leica lens is a 21mm f/2.8 Elmarit. While it is my favorite for this type shot, I sometimes want something even wider. Leica makes an 18mm but that is not significantly different from my 21mm, plus it is expensive.  Enter the Voigtlander 12mm and 15mm lenses.  Both are relatively inexpensive at $799 for the 12mm, and $599 for the 15mm -- actually downright cheap by Leica standards.  The electronic viewfinder on the new Leica M makes these lenses all the easier to use, and save you from having to purchase an optical finder for them.

The maximum apertures on these lenses are nothing to write home about, but for the price, I'm willing to work around that problem, especially since I use them mostly outdoors and like to work with them stopped down to achieve maximum depth and sharpness. And after all, you're not exactly seeking good bokeh from a super-wide angle lens.

A Voigtlander 15mm Super Wide Heliar lens mounted on a Leica M (240) with a Voigtlander 12mm Ultra-Wide Heliar next to it.
The 12mm f/5.6 Ultra Wide Heliar, delivering a 121° angle of view, is the widest rectilinear focal length available for full frame cameras.  The 15mm f/4.5 Super Wide Heliar has a more practical 100° angle of view.  By comparison, my 21mm lens has a 90° angle of view. Both Voigtlander lenses produce sharp images, even into the corners of the frame, particularly when stopped down a bit.

Sounds good so far.  So where's the catch?

The first problem is that ultra wide angle lenses and digital sensors have a hard time mixing. This is particularly true of the Leica M cameras where the sensor and sensor software are computed to deliver perfect images with Leica lenses.  My 21mm Elmarit works flawlessly. When other super wides are used strange things happen. Heavy vignetting takes place along with color shifts in the corners and edges of the frame.  It is so bad with the Voigtlander lenses that it would be a deal breaker were it not for a handy piece of share-ware software called, Cornerfix.  Cornerfix does what the firmware built into most camera does: It corrects for the aberrations between the lens and the sensor. Admittedly, this adds an extra step in the post processing of images, but I find it a small price to pay for the results it delivers.

Here is how it works: With the lens in question mounted on the camera and set to infinity (focus doesn't matter),  you take a photo of a large white card surface that is evenly lit, preferably with soft daylight. Next you open this image in Cornerfix and use the "Create" option under Lens Profile to analyze and correct the image to pure white. You save this lens profile for future use. Then, when you have a lens that needs correction, you open it, open the corresponding lens profile, and the image is corrected in no time at all.  What is more, Cornerfix has a batch processing feature so you can correct an entire directory of images with the same profile.  Nice!

This shows the Cornerfix correction of a white card photo taken with the Voigtlander 15mm lens.  It has heavy vignetting and red tinting on the sides.  The white image on the right is the same photo after Cornerfix has corrected it.  This corrected image will be saved as a control for future shots taken with this same lens.
You will notice that the vignetting on the test image is quite heavy. This can cause noise problems with actual images. The corners are often several stops darker than the central area. In opening up the dark corners, you  are effectively boosting the ISO and so adding a bad type of noise to the area. To counter act this I set my Leica to over expose by at least one full stop. Cornerfix can be the set to both open the shadows and lower the central highlights at the same time. This will even out the overall exposure and not result in as much noise in the corners.

I have found it best to code the lenses so that the Leica M will read them as a 21mm f/2/8 11134 and make some corrections to them accordingly. Of course this means that the image data lists them as a 21mm lens, but it does provide the correct f/stop info.

Below are a few images taken with the 15mm Super Wide Heliar. As you can see, one of the things I like to do with these lenses is include a sun burst. Links to the hi res files are included below.

This image and those below are sharp all the way into the corners. Due to the extreme lighting differential between the sun and the deep shadows in the World Trade Center on the left, there is residual noise in the lower left corner where Cornerfix lightened the dark vignette. In the building on the right you can also see a typical sample of moiré, a result of the Leica not having an anti-aliasing filter over its sensor. Click here to download the hi res version.

Click here to download the hi res version.

World Trade Center construction site.
The image below of a church interior was taken with the 12mm Ultra Wide Heliar. Some correction had to be done for fringing on the blown out windows along the edges of the frame, but this is typical with any lens in a situation such as this and easily corrected in Photoshop.  Even at f/5.6 the depth of field is astounding with this lens.

This interior church view was taken at 1600 ISO. I could not use a tripod and needed to keep the shutter speed high enough to hand hold the camera. For this reason I did not over-expose the shot to brighten the vignetted corners, and excessive noise did build up in those areas after treatment of the image in Cornerfix. I fixed some of the noise when bringing the RAW image in through Photoshop Bridge, but left the rest of it uncorrected so you can see the problem in the hi res download.  Click here to download the hi res version.
If you are planning on purchasing either of these lenses, you can help support this site at no extra cost to you by purchasing from one of our affiliate sellers listed below -- and thanks for your support.


The Voigtlander Heliar Ultra Wide-Angle 12mm f/5.6 is available at:  BH-Photo   Amazon  
The Voigtlander Super Wide-Heliar Aspherical II 15mm f/4.5 is available at:  BH-Photo  Amazon 

Tidak ada komentar:

Posting Komentar