Mu-43 Hall of Famer
- Jan 29, 2010
- South Gippsland, Australia
- Real Name
- Ray, not Oz
I was thinking about the problems that Fotodiox had with their first focal length reducing adapters.
Interesting indeed and it would be nice to see what cameras have what thickness of glass in front of their sensors!
So, even if the piezo shaker doesn't shed all of the dust particles, you'd have to work with very tiny apertures to see some of the smaller particles stuck to that filter stack..
Again, confused. Regardless of the aperture the image circle would be the same size, right?
I think the danger is possible damage to the image stablisation system.1) If there's all this glass in front of our sensors, why are we worried about cleaning them ourselves? NEX and Pentax Q clearly has glass. I thought my PM2 had nothing but the sensor. So, I CAN touch it!
Focal reducers really give a 'whoa' result. Its kinda amazing the first time you are in your image editor looking over results. Actually I could see something wonderful was up through the evf.2) I'm not understanding how this will affect anything. We here have tried hundreds of adapted lenses with very good, predictable results. What the article and you guys are saying makes sense, however, I'm not seeing any lack of quality.
Have a look at the Metabones Speedbooster white paper on page 5 - http://www.metabones.com/assets/a/stories/Speed Booster White Paper.pdf. The first picture quite clearly shows the effect a piece of flat glass has on the light rays. It also suggests to me that the Metabones Speedbooster for the m43 mount takes the ~4mm filter into account. Also remember that some of the long tele lenses with drop in filters recommends to have simple uv/skylight filter in place while not using any other filter, because a filter in that location is part of the optical design.3) Speed booster: the glass simply makes the image circle of the 35mm lens smaller and thus faster and wider. Since you're using a higher percentage of the intended image circle, sure, I can see how this might be better. But I don't see how the sensor stack could be making anything better or worse. I'm confused.
Ignore fortwodriver, it has nothing to do with dirt.Again, confused. Regardless of the aperture the image circle would be the same size, right?
I'm happy because there is choice in the market place for focal reducers. Roxsen is selling a decent one. Metabones is selling their Speedbooster which was designed by Brian Caldwell, the gent in the article. From the pdf linked above and Brian's comments in the article, it seems very likely that the Speedbooster design is taking the sensor stack into account giving very good results. Its not clear if the Roxsen does. When I bought mine I took a chance on Brian's reputation on his previous designs, and feel my purchase decision have been right for me.So, in short, why is finding out the thickness of the sensor stack making those who use speed boosters happier? And, if a flange distance of a certain mount is X, it will be X regardless. You don't even need to know the thickness of the sensor stack, right?
A dirty little secret in digital photography is that the filter pack (low-pass filter + infraredfilter + sensor cover glass) found in virtually all digital cameras can contribute significant aberration to the image when a lens designed for film is used. This problem is particularly troublesome for very fast lenses. The Speed Booster corrects this defect, and automatically corrects for filter pack aberrations regard less of the objective lens used.
So, in short, why is finding out the thickness of the sensor stack making those who use speed boosters happier? And, if a flange distance of a certain mount is X, it will be X regardless. You don't even need to know the thickness of the sensor stack, right?