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Speed booster for NEX

greypilgrim

New member
I'm not sure I understand what a "full frame version of the m43" is??:confused:
Sorry, it is what I think of it as.

This would be a version of the Speedbooster that would pull the entire image circle down to cover the m43 sensor. Similar to what is being done for the APS-C size sensors of the Nex right now. Thus getting the same angle of view from my FF lenses on the m43 body as I would get on a FF body. This would be instead of ending up with a 1.4x multiplier on m43...


So perhaps an FF equivalent angle of view? Or the .5x focal reducer for M43? Pipe dream, I know, and I plan on being fully happy with the .71x version when it becomes available for Nikon to m43.

But that is why I am interested in the potential of the Nikon to Fuji version as well (I'm not a Nex fan ergonomically). Having that adapter would get me to being able to use my nikkors at an equivalent angle of view that I had with them on film.

Doug
 

mazor

New member
I'm not sure I understand what a "full frame version of the m43" is??:confused:
I think he is hoping there will be a FF to m4/3 version of the speed booster eventually. Imagine that though, the glass will look quite odd on mft bodies as they are soo small, plus, imagine the light you would get from reducing from 1.0 crop to 2.0 crop. Would that equate to 2 stops more light? So a 2.8 full frame lens would become a f1.4 lens on m4/3.
 
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Vivek

Guest
Very interesting result Vivek!

FWIW, any UV capability is purely coincidental - its not something that I considered when doing the design. Assuming perfect coatings (i.e., just accounting for the intrinsic absorption of the glass) I calculate the following transmission values for the Speed Booster:
400nm - 94%
390nm - 90%
380nm - 81%
370nm - 60%
365nm - 49%

I can't do any calculations below 365nm because one of the glass types (S-TIH1) basically has zero transmission at 360nm and below. So I wouild assume that 365nm is pretty much the limit. The coatings are an efficient multilayer design tuned for the visible, so they will definitely cause a significant drop in transmission for the values I've given above.

Also, the Speed Booster will suffer from a large amount of chromatic aberration in the UV band. Did you re-focus when you added the Baader filter?

By contrast, the Speed Booster actually works very well in the near infrared, with surprisingly low chromatic aberration all the way out to 1.0 microns. The coatings will also be better in the IR than they are in the UV.
Thanks a bunch for the data, Brian!

Regarding CA- absolutely none whatsoever! In fact, I am yet to see any objectionable or even noticeable CA in near UV shots taken with any lens! Least of my worries. If I did not hand hold that 1/10s test shot, it would have been clear how sharp an image can be obtained (as I saw it in live view).

Re: Focus shift: This is also one thing that is of no concern to me with a live view cam. Ever since I started shooting with one, I have forgotten what a menace it was with a DSLR and shooting blind. With the NEX also, I can see, magnify a region 8X and focus before tripping the shutter.

Yes, you are correct about the near IR performance. No issues there at all. The Speed Booster work very well there. :thumbs:
 
V

Vivek

Guest
The Noflexar (my sample which is original in a Nikon F mount) does not focus to infinity and just avoids touching the SB optics.


Untitled by Vivek Iyer, on Flickr

It does quite well in near UV. If I use it as is, I can have focus from ~2.5m to 10cm!

At the moment I only have fuzzy examples (out of focus). I am quite impressed with the whole set up though. Useful. :)
 

greypilgrim

New member
I think he is hoping there will be a FF to m4/3 version of the speed booster eventually. Imagine that though, the glass will look quite odd on mft bodies as they are soo small, plus, imagine the light you would get from reducing from 1.0 crop to 2.0 crop. Would that equate to 2 stops more light? So a 2.8 full frame lens would become a f1.4 lens on m4/3.
See my response above, but yes, reducing the FF image circle down to the m43 sensor size is the idea.

Btw, they would look no odder than using them on the Nex now. That actually is the point of the Speed Booster:

"Finally utilize Full Frame Lenses on mirrorless cameras today"

Vivek has been using a number of Nikkors that I have already. 45mm, 20mm f3.5, etc...

Doug
 
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Vivek

Guest
Doug, I have only showed pictures from the 20/3.5 AiS (gem of a lens!), I think.

The 28/2.8 AiS is just awesome! Devoid of any corner problems or even distortion at f/2.8 already! Will have to go out with it next time and snap some pics.
 

mazor

New member
nice doug, I think it will eventuate for m4/3 whereby a FF lens becomes 1.5x crop when used with speedbooster, hence ability to reuse the same premium quality optic found in the current speedbooster for nex or fuji.

What would be amazing if they completely redeveloped the speed booster optic to allow proper FF to m4/3 with 1.0x crop. The compressing would be approx 2 stops extra.
 

brianc1959

New member
nice doug, I think it will eventuate for m4/3 whereby a FF lens becomes 1.5x crop when used with speedbooster, hence ability to reuse the same premium quality optic found in the current speedbooster for nex or fuji.

What would be amazing if they completely redeveloped the speed booster optic to allow proper FF to m4/3 with 1.0x crop. The compressing would be approx 2 stops extra.
Although the m43 versions of the Speed Booster will have the same 0.71x magnification factor as the NEX version, the optics are completely different. The reason is that by optimizing for a smaller format it is possible to achieve slightly higher performance As a result, corner performance on m43 will be a bit better than if the NEX optics were used.

A 2-stop Speed Booster is possible if you use slow lenses with *lots* of rear working space (e.g., long telephotos and telescopes), but that would not be a very interesting product IMO.
 

mazor

New member
Any idea when the real Nikon to NEX SB becomes available?
if you want to uase AIS nikors, just get the Canon ef to nex and use an adapter, hence you can adapt multiple types of lens to nex.


If a nikon to nex adapter comes out, it should have ability to control electronic apertures from modern nikkor lens as well as VR, similar to what the ef to nex
 
I believe they are all 0.71x reduction.

Equivalent DOF for m4/3 would be (2 x 0.71 x the f-stop) (2 being the crop factor of m4/3)
The reason for 0.71x is that for the adapter to gain a stop, the image area compression must be equal to what root square of 0.5 result comes too... i.e. =0.71, this means that if a 4/3 lens image area would have to be covered by a 35mm FF lens exactly, the compression should be of half the area of the image circle radius than what FF is and thus the reduction would cause ...two stops of aperture gain (i.e 0.71x0.71)!!!! There would have to be some problems though, with some lenses that are only able to cover a 2:3 image area in FF, a few lenses that would cause viggneting in case the FF area was 4:3 (this is because the diagonal in 4:3 is slightly larger than 2:3 at the same width) but of the same width ....i.e. 36mm! :chug:
 
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greypilgrim

New member
Doug, I have only showed pictures from the 20/3.5 AiS (gem of a lens!), I think.

The 28/2.8 AiS is just awesome! Devoid of any corner problems or even distortion at f/2.8 already! Will have to go out with it next time and snap some pics.
I thought I saw you using the 45mm pancake also?

I have the 28mm f2 which renders beautifully for me on a DX nikkor, so thinking about it on an m43 with the speedbooster is something to anticipate.

I have lots of others to play with...

Doug
 

greypilgrim

New member
Although the m43 versions of the Speed Booster will have the same 0.71x magnification factor as the NEX version, the optics are completely different. The reason is that by optimizing for a smaller format it is possible to achieve slightly higher performance As a result, corner performance on m43 will be a bit better than if the NEX optics were used.

A 2-stop Speed Booster is possible if you use slow lenses with *lots* of rear working space (e.g., long telephotos and telescopes), but that would not be a very interesting product IMO.
Hi Brian,
I am not completely following this. Is it because the size of the glass in a 2 stop speedbooster would be such that it would interfere with the lenses physically?

My primary interest is indeed using the wider lenses at their "original" angle of view. Although I will be curious how longer lenses do in terms of increased image quality using the speedbooster as well.

Doug
 
Hi Brian,
I am not completely following this. Is it because the size of the glass in a 2 stop speedbooster would be such that it would interfere with the lenses physically?

My primary interest is indeed using the wider lenses at their "original" angle of view. Although I will be curious how longer lenses do in terms of increased image quality using the speedbooster as well.

Doug
You won't be able to use the current SB to achieve "original" AOV on micro 4/3rds Brian, what it will be, is that the crop factor of "original" AOV will be reduced from 2x to 1.4x i.e. the root square of 2... (1.4x1.4=2 (aprox.)) this is because you gain one stop of aperture... :lecture:
 
Hi Brian,
I am not completely following this. Is it because the size of the glass in a 2 stop speedbooster would be such that it would interfere with the lenses physically?

My primary interest is indeed using the wider lenses at their "original" angle of view. Although I will be curious how longer lenses do in terms of increased image quality using the speedbooster as well.

Doug
I've explained this a little before Doug, the 4/3rds crop factor may be 2x as far as width of sensor is concerned, but it is less as far as sensor diagonal is concerned... This is because FFsensors are of 3:2 ratio while O&Pan are of 4:3 ratio... so, a 2stop SB would mean that some FF lenses would be compressed off their limits and some more would expose problems that normal use wouldn't show... also, some APS-c lenses that now work, they would have to be excluded... in other words there are many complexities involved that among others could harm the reputation of a great product... better as is then... :chug:
 

brianc1959

New member
If true, I can only hope that:
1) the lens isn't "fixed", but is interchangeable
2) the camera has a proper EFV (like the NEX-7)
3) the flange distance is short
4) they haven't cluttered up the optical path to the sensor so that a Speed Booster will be possible.
 

brianc1959

New member
Hi Brian,
I am not completely following this. Is it because the size of the glass in a 2 stop speedbooster would be such that it would interfere with the lenses physically?

My primary interest is indeed using the wider lenses at their "original" angle of view. Although I will be curious how longer lenses do in terms of increased image quality using the speedbooster as well.

Doug
A 2-stop general-purpose speed booster in a cramped space has to have alot of optical power. This in turn creates a ton of under-corrected field curvature that just can't be corrected. As a result, the optical performance would be horrendous, and I'm just not interested in that kind of product.
 
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