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Speed booster for NEX

V

Vivek

Guest
Vivek, just wondering, the ever so slight corner softness when using the speed booster with fast aperture EF lens when used wide open, does this apply to slower wide angle prime lens as well?, eg 15mm f3.5 say?

The reason I ask, is if I do get a speed booster, not only would I enjoy the added narrow depth and extra light, but also would like to use it for my ultra wides to capture landscapes which typically use infinite focus
Here are a few sample shots (dreary day, can't help it) from a Sigma 15-30 zoom at the wide end.

Upclose:


Untitled by Vivek Iyer, on Flickr
NEX-6, Speed Booster, Sigma DG 15-30 f/3.5-4.5, Effective 10mm, f/2.5

At infinity:


Untitled by Vivek Iyer, on Flickr
NEX-6, Speed Booster, Sigma DG 15-30 f/3.5-4.5, Effective 10mm, f/7.1

Extreme corner crop of that:


Untitled by Vivek Iyer, on Flickr

This lens and the sample is not without problems. The bulbous front element of this zoom is also made of of Plastic.
 
V

Vivek

Guest
Swirly bokeh from an yesteryear's lens is fully preserved .


Untitled by Vivek Iyer, on Flickr


Untitled by Vivek Iyer, on Flickr
NEX-6, Speed Booster, Enna Lithagon II 85mm f/1.5, Effective f/1


The Biotar 75/1.5 has a similar bokeh. I still am waiting for a M42 mount adapter to arrive.
 
:talk028:
The possibilities of the speed booster on the m43rds are even more than the one for the APS-C sensors.

Consider the Sigma 8-16 zoom made for APS-C. With 0.71x factor, on the m43rds, it becomes the widest ultrawide possible.

The white paper I linked above discusses quite a few possibilities.

If you look carefully, you would also find that there are two separate optical designs- one for m43rds and another for APS-C. There are specific reasons for this.

Personally, I would consider using my OM lenses with the speed booster on the NEX'. The OM 50/1.2 which is the lightest and more compact of all the 35mm lenses being the most attractive.
Actually you can't do that.... you have to use a FF lens on the adapter... What is compressed is the image circle to a smaller one, so lenses with a smaller image circle will be compressed to an even smaller image circle and will be unable to cover the whole image area even if it's one of 18mm width.... :facesmack:
The reason for the different optical design for 4/3rds is because the light sensitive area to mount distance is different than NEX....:talk028:
 
V

Vivek

Guest
:talk028:
Actually you can't do that.... you have to use a FF lens on the adapter... What is compressed is the image circle to a smaller one, so lenses with a smaller image circle will be compressed to an even smaller image circle and will be unable to cover the whole image area even if it's one of 18mm width.... :facesmack:
The reason for the different optical design for 4/3rds is because the light sensitive area to mount distance is different than NEX....:talk028:
:confused:
 

brianc1959

New member
:talk028:
Actually you can't do that.... you have to use a FF lens on the adapter... What is compressed is the image circle to a smaller one, so lenses with a smaller image circle will be compressed to an even smaller image circle and will be unable to cover the whole image area even if it's one of 18mm width.... :facesmack:
The reason for the different optical design for 4/3rds is because the light sensitive area to mount distance is different than NEX....:talk028:
You can use DX format optics on the upcoming m4/3 Speed Booster, and an example is shown in our white paper using the Nikon 35/1.8 DX lens.

However, its important to note that the m43 Speed Booster will have the same 0.71x reduction factor as the NEX version. This is a bit less than the optimal value of 0.75x you would want for converting DX lenses to m43 format. As a result, DX format lenses will appear slightly wider when converted to m43 via a Speed Booster than they do on a DX format sensor.

For many lenses such as the Nikon 35/1.8 or Sigma 30/1.4 this is purely beneficial. However, its possible that a few ultrawides may show some corner vignetting since we are revealing more of their image circle than was originally intended.

Another thing to keep in mind with the upcoming m4/3 version is that some DX format ultrawides have a non-removable lens shade. Due to the aspect ratio mismatch such a shade can cause vignetting along the long sides of the final m4/3 image.

Of course, if you are using a Black Magic camera these two issues go away because of the slightly higher crop factor :cool:

At some point we may decide to build a special 0.75x Speed Booster for adapting EF-S and DX optics to m4/3, but we are starting out with a 0.71x version because it gives a full stop speed increase and it works better with FF optics.

The m4/3 version uses different optics than the NEX version mainly because we were able to improve optical performance by optimizing for the smaller format.
 
You can use DX format optics on the upcoming m4/3 Speed Booster, and an example is shown in our white paper using the Nikon 35/1.8 DX lens.

However, its important to note that the m43 Speed Booster will have the same 0.71x reduction factor as the NEX version. This is a bit less than the optimal value of 0.75x you would want for converting DX lenses to m43 format. As a result, DX format lenses will appear slightly wider when converted to m43 via a Speed Booster than they do on a DX format sensor.

For many lenses such as the Nikon 35/1.8 or Sigma 30/1.4 this is purely beneficial. However, its possible that a few ultrawides may show some corner vignetting since we are revealing more of their image circle than was originally intended.

Another thing to keep in mind with the upcoming m4/3 version is that some DX format ultrawides have a non-removable lens shade. Due to the aspect ratio mismatch such a shade can cause vignetting along the long sides of the final m4/3 image.

Of course, if you are using a Black Magic camera these two issues go away because of the slightly higher crop factor :cool:

At some point we may decide to build a special 0.75x Speed Booster for adapting EF-S and DX optics to m4/3, but we are starting out with a 0.71x version because it gives a full stop speed increase and it works better with FF optics.

The m4/3 version uses different optics than the NEX version mainly because we were able to improve optical performance by optimizing for the smaller format.
What you are saying Brian, is that most APS-c lenses have larger image circle than what is needed to cover an APS-c sensor ...no? But again, using some of this extra area, wouldn't affect edge and especially corner image quality? ...Wouldn't it enhance vignetting and perhaps add more distortion than the original lens characteristics?
 
V

Vivek

Guest
DX Nikkor 10.5mm with the SB on NEX-6. Effective f/2, 7.5mm. The top right orange stuff is slightly behind (!) the lens. The original built in hood on the lens is still there. The results are quite similar to the ones from FF Canon 5D or a Nikon camera.


Untitled by Vivek Iyer, on Flickr
 

brianc1959

New member
DX Nikkor 10.5mm with the SB on NEX-6. Effective f/2, 7.5mm. The top right orange stuff is slightly behind (!) the lens. The original built in hood on the lens is still there. The results are quite similar to the ones from FF Canon 5D or a Nikon camera.
Interesting experiments, and nice photo of the rilling on the inside of your lens hood!

Since the hood on the 10.5mm DX Nikkor is shaped for a 3:2 format you will probably get some vignetting along the upper and lower parts of the image when cropped to m4/3 proportions, but perhaps not along the left and right hand sides.

The actual m4/3 SB will behave similarly to your experiment with the NEX version, with the main difference being improved corner performance.

On a related note, I have noticed that at least one person posting on DPReview has been successful in using a Canon EF-S lens with the NEX SB by removing a rear plastic shroud. Apparently there was no glass-glass collision. YMMV, of course.
 
Thanks for the post Vivek! ...it's exactly what I meant :thumbup: ...However, what Brian says (I think...) is that due to the lesser image area width, the SB for 4/3rds, allows (almost) the APS-c image circle to just about cover the whole 4/3rds area, especially with some lenses that have wider image circle than what is necessary to cover the APS-c sensor...:loco: ...I don't deny that this may be the case, but using more area of what the lens designers allowed and users buy it for, it would provide a lens with different (worst) characteristics than it is expected from it...:lecture: I would stick with FF lenses only for the SB... Actually, I will buy the SB immediately when it will be available for Nikon lenses to NEX, since I recently changed the videocameras we where using in "Fotometria" to interchangeable lens ones with NEX mount and I own a huge collection of Nikkor FF lenses which I now use through adapters...:clap: I suppose you used a N-C adapter to mount the nikkors on your SB ...no? :salute:
 
V

Vivek

Guest
On a related note, I have noticed that at least one person posting on DPReview has been successful in using a Canon EF-S lens with the NEX SB by removing a rear plastic shroud. Apparently there was no glass-glass collision. YMMV, of course.
I found that (the thread that K-H linked here) and find that rear baffle construction of EFS 10-22 very similar to those of the IX-Nikkors. I still have a 30-60 IX-NIkkor (modified) somewhere. Your caution is apt as not all may work.
 
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brianc1959

New member
Thanks for the post Vivek! ...it's exactly what I meant :thumbup: ...However, what Brian says (I think...) is that due to the lesser image area width, the SB for 4/3rds, allows (almost) the APS-c image circle to just about cover the whole 4/3rds area, especially with some lenses that have wider image circle than what is necessary to cover the APS-c sensor...:loco: ...I don't deny that this may be the case, but using more area of what the lens designers allowed and users buy it for, it would provide a lens with different (worst) characteristics than it is expected from it...:lecture: I would stick with FF lenses only for the SB... Actually, I will buy the SB immediately when it will be available for Nikon lenses to NEX, since I recently changed the videocameras we where using in "Fotometria" to interchangeable lens ones with NEX mount and I own a huge collection of Nikkor FF lenses which I now use through adapters...:clap: I suppose you used a N-C adapter to mount the nikkors on your SB ...no? :salute:
Yes, since the 0.71x version of the Speed Booster for m4/3 will show a bit more of the image circle of DX lenses than would be seen if you mount that same DX lens on a DX format camera. Whether you like it or dislike it will undoubtedly depend on what lens you use. Of course, you can always crop out the offending bits!

Personally, I'm starting to like the idea of a special 0.75x Speed Booster to adapt DX and EF-S to m4/3. The relaxed magnification would allow for incredibly high optical performance that is really needed on m4/3.
 
V

Vivek

Guest
Very nice, John. Not only the smooth OOF rendition but the image clarity in the focused areas are top notch!
 
V

Vivek

Guest
Other than my own curiosity, I have had some queries if the SB is useful for UV captures.

Here are two shots using the UV-Nikkor 105/4.5S lens.

Visible:


Untitled by Vivek Iyer, on Flickr
Modified NEX-C3, Speed Booster, UV-Nikkor 105 f/4.5, Effective f/4, UV-IR cut filter, ISO1600, 1/1000s

Reflected UV (false color)


Untitled by Vivek Iyer, on Flickr
Modified NEX-C3, Speed Booster, UV-Nikkor 105 f/4.5, Effective f/4, Baader U 2" filter, ISO1600, 1/10s, UV capture

The Baader U 2" filter transmits between 320nm to 390nm. Given ~7 stop drop while going from Visible light to UV (natural UV content of daylight), it appears that the Speed Booster has excellent UV transmission! :thumbs:

Now, I have to look for a Brian Caldwell 60/4 UV-Vis-IR Apo Macro lens!

One note of caution:

Anyone wanting to use the 35mm f/3.5 Noflexar lens be beware that the lens would damage the SB optics at infinity!
 

greypilgrim

New member
The actual m4/3 SB will behave similarly to your experiment with the NEX version, with the main difference being improved corner performance.
Looking forward to the M43 version. I've been watching this thread every day to see the results people are getting.

I've even pondered getting an XE1 at such time as the Nikon to Fuji speedbooster becomes available (unless of course there really was a "full frame" version of the m43 coming ;-))

Doug
 

brianc1959

New member
Other than my own curiosity, I have had some queries if the SB is useful for UV captures.

Here are two shots using the UV-Nikkor 105/4.5S lens.
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.
 

brianc1959

New member
Looking forward to the M43 version. I've been watching this thread every day to see the results people are getting.

I've even pondered getting an XE1 at such time as the Nikon to Fuji speedbooster becomes available (unless of course there really was a "full frame" version of the m43 coming ;-))

Doug
I'm not sure I understand what a "full frame version of the m43" is??:confused:
 
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