EXCERPT page containing first few paragraphs. 2020-09-19 19:16:34
UA_SEARCH_BOT_null @ 220.127.116.11
Sony’s press discussion places very strong emphasis on MTF of 50 line pairs per mm (lp/mm) in the new G Master (GM) lenses. But its approach is self contradictory, and without any rigor:
- Sony MTF chart is at 10 and 30 lp/mm... where is the 50 lp/mm data emphasized so strongly in the Sony press conference? This kind of disconnect undermines credibility. MTF at 50 lp/mm (or even 40) is far more demanding than at 30 lp/mm.
- Sony MTF is computed from a design, not measured from a real lens. Real lenses have to be built, and can at best only approach the theoretical computed performance and only if built to perfection. When actual lenses are examined in field use, weaknesses pop out.
- Sony MTF does not take diffraction into account. While this no bearing on the f/1.4 chart, the f/8 chart is pure fantasy (impossible). It tells us to expect strong performance at f/8, but it does not tell us what a real lens measured will deliver. At f/8, MTF of the Zeiss Otus 85mm f/1.4 APO-Planar (best 35mm lens ever made) even at 40 lp/mm falls short of 80% MTF. Another ding to credibility—it’s not real. Moroever, in real field conditions, internal reflections can drop MTF at f/8 significantly.
Article continues for subscribers...
Diglloyd Guide to Mirrorless is by yearly subscription. Subscribe now for about 25 cents a day ($90/year).
BEST DEAL: get full access to ALL 8 PUBLICATIONS for only 68 cents a day ($249.95)!
Diglloyd Guide to Mirrorless offers comprehensive integrated coverage of most APS-C and full frame mirrorless cameras and lenses.
Special emphasis is placed on Sony full-frame, including Sony lenses and the high performance Zeiss Batis and Zeiss Loxia lenses plus Rokinon/Samyang and others. Fujifilm X, Olympus and Panasonic M4/3, Sigma dp Merrill and dp/sd Quattro are also covered in depth. Years in the making, it offers a wealth of material for choosing and using a mirrorless camera.
- Make better images by learning how to get the best results right away. For example, the best way to set up your Sony camera.
- Save money by choosing the right lens for your needs the first time, particularly with the numerous lenses available for Sony.
- Make better images, a sort of “cheat sheet” saving yourself months or years of ad-hoc learning—best practices and how-to and processing parameters are discussed and shown.
- Jaw-dropping image quality found nowhere else utilizing Retina-grade images up to full camera resolution, plus large crops.
- 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.
Want a preview? Click on any page below to see an excerpt as well as extensive blog coverage, for example on Sony.