Metabones Smartadapter IV with Sigma 15mm

Hi,

It is time to go full-frame for me and after a lot of evaluations with Pros and Cons of stepping back to DSLR vs stay Mirrorless I finally ordered a Sony A7RII + Nauticam housing. I think the native Sony 28mm lens with Fisheye adapter will be a bit too bulky, so I decided to choose the well proven Sigma 15mm instead (Canon EF) + a Metabones Smart Adapter.

I have read that the version IV of the adapter should work with Autofocus on the Sigma Fisheye. Is there anyone here who can confirm this and have tried this setup, or with another adapter brand?

It works (kind of) but in my hands at least it is terribly slow.

Bill

Perhaps with the updated firmware it will work, but when I bought the MK IV Metabones and Sigma 15mm to use with my Sony a7r, it did not autofocus at all. So I bought the Canon 8-15mm and tried that. It worked but really slow (might be faster on the a7r II). I finally ended up with the Sony 28mm and the wide angle and fisheye converters. The autofocus is fast and accurate. The optics are very good with the wide-angle converter, and pretty good with the fisheye (not as sharp, I would say, as the Canon 8-15, but better results overall because of the faster focusing)

According to Brian Smiths it seems like it should work with the latest firmware of the Metabones. I hope that it's fast enough,

http://briansmith.com/sony-a7rii-canon-ef-smart-adapter-tests/

Metabones: Good speed and accurate PDAF AF-C and AF-S with Wide, Center and Flexible Spot
Fotodiox: Manual Focus only – but adapter provides electronic aperture control
Viltrox: Manual Focus only – but adapter provides electronic aperture control

The Backscatter A7RII review suggests the Sigma has issues with the apeture, but that the Canon 8-15 works well and focuses fast.

http://www.backscatter.com/learn/article/article.php?ID=234

I'd look at the Sony 28 plus Nauticam's new WWL-1 lens. It looks to be very wide with sharp corners. the 28 fits into a small flat port with 67mm thread. Much smaller than the 16-35 to be sure.

Other than that I'd shoot a Nikonos 15FE if you want a small sharp fisheye.

Edward posted some shots here: https://nauticam.smugmug.com/HousingTests/A7R-II/

I just got the Sigma and Metabones IV and upgraded to version v0.45

The autofocus is really really fast together with the A7RII, and I have not experienced any problems with the aperture as described in the Backscatter review.

Manual focus using the focus gear may be an issue. I can switch to manual focus on the camera, but I can´t access the mechanical switch on the lens to release the focus motor (will it be harmed if not released?).

However that has nothing todo with the Sony or Metabones and is probably a common issue for the Sigma 15mm.

Will take it for a test under water behind the dome next week!

I just got the Sigma and Metabones IV and upgraded to version v0.45

The autofocus is really really fast together with the A7RII, and I have not experienced any problems with the aperture as described in the Backscatter review.

Manual focus using the focus gear may be an issue. I can switch to manual focus on the camera, but I can´t access the mechanical switch on the lens to release the focus motor (will it be harmed if not released?).

However that has nothing todo with the Sony or Metabones and is probably a common issue for the Sigma 15mm.

Will take it for a test under water behind the dome next week!

Tobbe, what dome/extension ring combination are you using the Metabones IV + Sigma 15mm with, out of curiosity? This may be the route I go if I choose the A7RII.

I'd look at the Sony 28 plus Nauticam's new WWL-1 lens. It looks to be very wide with sharp corners. the 28 fits into a small flat port with 67mm thread. Much smaller than the 16-35 to be sure.

 

Other than that I'd shoot a Nikonos 15FE if you want a small sharp fisheye.

 

Edward posted some shots here: https://nauticam.smugmug.com/HousingTests/A7R-II/

Interesting option. My understanding from Interceptor21's review of the WWL-1 though is that the field of view is still not quite 180 degrees on the diagonal, so it'll be a bit narrower than a true fisheye. Plus, the WWL-1 is very heavy (negative underwater unlike a dome, I presume) and quite expensive. It would be great if someone could compare this with the Sony 28 + Fisheye adaptor inside a regular dome or an adapted Sigma 15mm fisheye or Canon 8-15mm fisheye.

Seems like there's a lot of choices for fisheye on the A7RII, even without a native fisheye lens (yet).

Isn't the Nikonos 15 a rectilinear WA lens rather than a fisheye?

 

Tobbe, what dome/extension ring combination are you using the Metabones IV + Sigma 15mm with, out of curiosity? This may be the route I go if I choose the A7RII.

 

I have the Nauticam 37303 A7 II Port Adapter + Nauticam 18810 N120 140mm optical glass fisheye port. That is Nauticams recommendation for the Sigma.

 

I have the Nauticam 37303 A7 II Port Adapter + Nauticam 18810 N120 140mm optical glass fisheye port. That is Nauticams recommendation for the Sigma.

Just curiosity: why not the A-mount sigma? Would it fit in the housing with the (bulky...) A to E af adapter?

BTW the n120 is a bit small for FF, has some limitations. If i try this option I'll go with a larger dome.

Just did some research. The only thorough review on it says the sony is rather soft on the edges with high CA already on land. After visiting this topic, realized the Sigma15 (& Tokina 10-17) is not much better and the canon 8-15 didn't raise the bar either. I'd say the converted 2/28 is probably not significantly worse than either domed solutions - of course for proper assessment one has to compare them shooting test charts.

I don't know, if there is a magic that renders soft/CA loaded corners better when packed in a dome (e.g. opposite "direction" of the distortions which compensates?) but I doubt.

Speaking of Metabones, I am curious if the AF works on older cameras as well (A7II).

Regarding weight, there are two factors: travel (dry) weight and underwater. Dry a decent dome also weighs 1-2kg. Balancing is an issue for both, a full-frame dome needs weights on its belly, the wwl-1 needs floats. Price-wise the difference is not much:

WWL1: ~1k$, flat port (N100): 330$, 2/28 lens: 350$

vs Sigma 15: ~500$, decent fisheye dome+gear+adapter: 1k$

The nikonos 15 is rectilinear, the 13mm piece is fisheye. Unfortunately rainbow unicorn category with its associated price tag and MF:(. IQ-wise true, these are THE PERFECT optics underwater, designed for UW use from the core by Nikon engineers.

the other issue with using canon + metabones + a7 series camera (at least in my experience) is that every now and then it bugs out and the screen goes black. Its a relatively easy fix as you just disconnect and reconnect the lens to the metabones, but when it happens during a dive it really sucks

It may be that the black screen bug is due to a defect in your particular unit. My first Metabones was very buggy. After weeks of trying to figure out how to make it work, I finally mailed it back to them (in Hong Kong), and they sent me a new one that worked fine.

One interesting aspect of the sel057fec converter or any true 180° fisheye vs the 120° WWL-1: the true fisheyes and the sony convertered solution indeed does 180° on the full frame and remains decent if doing s35 cropped video - which gives the best IQ for video on the 7rII. Cropping the wwl-1 will bring <100°. Alternative would be to pair the WWL-1 with a 20mm lens - then however one would be limited to the S35 crop throughout the dive and still no more than 120° FOV.

Thanks for doing this research, Tamas, and for posting your findings. I too am interested in the best wide angle option for the A7RII. I'm also particularly drawn to the versitility of the fisheye zooms (Canon 8-15, Tokina 10-17). Some thoughts/questions:

1. Have you considered/researched using the Tokina/Canon with a 1.4x or 1.5x teleconverter to be able to have both a 180* fisheye and a tighter 110-100* fov for close-focus wide angle macro or sharks, etc? Any idea if this would work with the metabones adapter? What kind of adapters, domes and extension rings would you need on a Nauticam housing?

2. I wonder if there's any option of using the WWL-1 with a kit zoom like you can on micro 4/3rds.

I used the Tokina 10-17mm with a 1.4x teleconverter extensively on the Nikon D700. That camera is only 12MP, but, on a good monitor, you can still plainly see the quality loss from the teleconverter (vs, for example, the Sigma 15mm with no teleconverter). It would be much more obvious on the 42MP Sony a7rII sensor. On the other hand, I've done some test shots with the Canon 8-15mm and Metabones on the 36MP a7r, and the image quality is phenomenal. The Tokina is a great lens, but you lose a lot, resolution-wise, by putting a teleconverter behind it, on top of whatever problems that might cause with autofocus.

Thanks for doing this research, Tamas, and for posting your findings. I too am interested in the best wide angle option for the A7RII. I'm also particularly drawn to the versitility of the fisheye zooms (Canon 8-15, Tokina 10-17). Some thoughts/questions:

 

1. Have you considered/researched using the Tokina/Canon with a 1.4x or 1.5x teleconverter to be able to have both a 180* fisheye and a tighter 110-100* fov for close-focus wide angle macro or sharks, etc? Any idea if this would work with the metabones adapter? What kind of adapters, domes and extension rings would you need on a Nauticam housing?

 

2. I wonder if there's any option of using the WWL-1 with a kit zoom like you can on micro 4/3rds.

I only researched the Tokina lens a bit, I concluded the glass is lesser quality than any of the other options we have on the table (sigma, 2/28+sony converter, wwl-1), simply too much CA with the modern sensors.

The problem with zoom lenses behind the WWL-1 is spacing. Specifically the 28-70mm kit zoom is a great lens for that, since it varies very little AND the lens protrudes the most at 28mm. The official port chart doesn't mention compatibility,

we should ask them before buying. Personally I'll prefer to go the 2/28 way (if I go FF at all in this round...).

Yesterday I upgraded my Metabones MK IV to the latest firmware, upgraded my a7rII to the latest firmware, and started trying out lenses. So far, focus has been fast and accurate with every Canon lens I have tried, including 8-15mm, 15mm, 20mm f2.8, 17-40mm f4L, 70-200mm f2.8L, and 100-400mm (old style). I'm noticing severe color fringing on the Canon 8-15mm (tested at 15mm). I don't have the Sigma 15mm with a Canon mount, so I can't do a direct comparison.

Could you post some shots demonstrating the color fringing on the Canon 8-15mm, Kogia? I'm thinking of going with that combination for my A7RII underwater rig -- are you saying that the image quality with the Metabones MK IV on the A7RII is much worse than on your previous Canon camera? Perhaps you could post a few comparison shots?

Sorry - deleted those test shots already. You've seen it before, I'm sure - purple fringe CA along edges of objects near outside edges and corners of frame. No, I'm not saying it's worse than on a Canon camera. I'm sure you'd see exactly the same thing on any camera with similar resolution, although I've never used this lens on a Canon, so I can't say from personal experience. The CA (chromatic aberration) comes from the lens, not the camera, but it's more apparent with higher resolution.

Kulupa - Your screen going black issue may be related to the sensor in the camera that switches between the viewfinder and the LCD screen. In the A7rII, this sensor is hyper-sensitive and may switch off the LCD (and switch on the EVF) anytime anything passes within inches of the VF. It varies between individual cameras. Mine turned out to be so sensitive that the LCD turns off whenever the back goes on the housing (regardless of the position of the switch on the housing for VF/LCD). So it was impossible for me to use the LCD with the camera in the housing until I found this workaround: http://reefphoto.com/kb.php?id=95