EXCERPT page containing first few paragraphs. 2021-12-02 20:18:43
UA_SEARCH_BOT_null @ 184.108.40.206
Distortion is very well controlled with the 17/4L, even forgetting its extreme angle of view.
The little distortion that exists is of the “wave” type: central barrel distortion transitioning to pincushion distortion well away from center. It’s barely noticeable in most scenes except to a trained eye, but once observed it’s there. Shifting less than the full amount will result in very mild barrel distortion (only), and the amount is minimal shifted in the short axis; it becomes more observable when shifted 12mm in the long axis.
One must keep things in perspective: by any comparison this distortion behavior is impressively good. Also, geometric perspectic is not optical distortion—use the shift feature to correct for camera tilt.
Article continues for subscribers...
Diglloyd Advanced DSLR is by yearly subscription. Subscribe now for about 16 cents a day ($60/year).
BEST DEAL: get full access to ALL 8 PUBLICATIONS for only 68 cents a day ($249.95)!
Diglloyd DAP is DSLR-oriented, but also contains workflow and other topics. Much of the focus is on Canon and Nikon but also Pentax and Pentax medium format.
Special emphasis is placed on lens evaluation, focusing on Canon and Nikon and Sigma lenses, but with a few others like Rokinon/Samyang.
- Make better images by learning how to get the best results right away.
- Save money by choosing the right lens for your needs the first time, particularly some of the new Sigma Art lenses vs Nikon and Canon.
- Workflow discusses image organization, raw conversion and post processing. Many examples show processing parameters for direct insight into how the image was converted.
- Jaw-dropping image quality found nowhere else utilizing Retina-grade images up to full camera resolution, plus large crops [past 2 years or so].
- Real world examples with insights found nowhere else. Make sharper images just by understanding lens behavior you won’t read about elsewhere.
- Aperture series from wide open through stopped down, showing the full range of lens performance and bokeh.
- Optical quality analysis of field curvature, focus shift, sharpness, flare, distortion, and performance in the field.