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Archive 2014 · A7s is great with all RF WA and UWA?

  
 
uhoh7
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p.1 #1 · p.1 #1 · A7s is great with all RF WA and UWA?


That's what I'm starting to hear, but have not done alot of peeping.

If that's true, it's a big deal.



"I have to say that the Sony A7s produces some of the cleanest, most pleasant images I've seen this side of a medium format system. "
Michael Reichmann
http://www.luminous-landscape.com/reviews/cameras/sony_a7s_first_impressions.shtml

OMG shutter is silent!

Everyone knows before me :
http://www.stevehuffphoto.com/2014/07/15/the-sony-a7s-a-new-camera-for-leica-m-lenses-by-ashwin-rao/



Aug 14, 2014 at 01:55 AM
Dustobub
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p.1 #2 · p.1 #2 · A7s is great with all RF WA and UWA?


I've switched from the A7r to the A7s. It is indeed significantly better but I wouldn't say it's great with all RF WA and UWA. That being said, it has reached a level that fulfills my original goal of having a small full-frame mirrorless camera with a complete (15, 28, 50, 90) RF kit. The extra low light capability and silent shutter (for when you need it) are just icing on top.

Here are some of my quick impressions:

CV Heliar 15 - Very good performance and a blast to use. Instead of the magenta color shift there is cyan shift, but it's to a much lesser degree. I'd say it only warrants Corner Fix about 30% of the time, but that's my personal opinion. I'm sure some would want to fix every shot. Corners and edges are sharp enough for me. Looks to be very similar to how it performs on an M9 but I can't do a direct comparison. This lens is a little treasure, especially for the price.

Zeiss 28 2.8 ZM - I really wanted this to be great, but there is still smearing in the corners and a large amount of field curvature - something I've been noticing more of and probably exists on the A7 and A7r as well. It's very easy to confuse smearing with field curvature, but unfortunately the Zeiss 28 has both with the A7s.

CV Ultron 28 f/2 - Performs much better than the Zeiss 28. Pretty much no color shift, though it's a little tough to tell with the vignetting when shot at large apertures. I haven't shot any Corner Fix profiles yet to really see if there's any shift. Corners are pretty good past f/4 but there is moderate field curvature at closer distances (again not quite sure if this is just the lens or more of the camera and the sensor glass toppings). Regardless, it's a very workable combo and has produced some very nice shots.

Zeiss 35 2.8 ZM - Very pleased that I kept this lens. I originally bought it for the A7r but it was a magenta mess. Now it's looking quite good. Definitely a bit of field curvature at close distances but I'll be keeping it.

I will try to post some pictures this evening or tomorrow. I'll also be testing out both the Hexanon 28 2.8 and the Zeiss 25 2.8 ZM next week. I'll post my impressions then.

-Dustin



Aug 14, 2014 at 03:21 PM
uscmatt99
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p.1 #3 · p.1 #3 · A7s is great with all RF WA and UWA?


Dustin,

Thanks for the post. I have the CV15, ZM25 and ZM35/2.8 as well, and have been disappointed with them on the A7. I'm especially heartened to hear the C-Biogon did well enough on the A7s to warrant your keeping it. If you have an opportunity, could you post an infinity shot from the C-Biogon and maybe a cropped corner with some detail? If not, your subjective impressions are much appreciated.



Aug 14, 2014 at 03:57 PM
Taylor Sherman
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p.1 #4 · p.1 #4 · A7s is great with all RF WA and UWA?


I'm curious about the 21 Super-Elmar and 28 Summicron-M.

I think Charles K has the A7S and the 21SEM, though I don't think I've seen a picture with the combo yet.




Aug 14, 2014 at 04:02 PM
Dustobub
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p.1 #5 · p.1 #5 · A7s is great with all RF WA and UWA?


Here are a few test shots from this weekend. I'll have some more walkaround photos later this week, but I'm currently battling some raw conversion issues with Aperture vs. Adobe Camera Raw (I'll probably create a new post for discussion).

These are from the A7s with Zeiss 35mm C-Biogon 2.8 taken from my apartment rooftop in NYC on a somewhat hazy day. There are four photos: one center focused at f/2.8, one center focused at f/8, one corner focused at f/2.8, and one corner focused at f/8. I also posted two crops to show where I was focusing.

https://www.dropbox.com/sh/ohl6wssq9j196wd/AADPjm4ZiZSrvnbRCMV8db_Aa

You can see that there is some significant field curvature with the C-Biogon. It's very usable, and has no color casting, but the field curvature does create problems depending on the shot, and certainly makes focus and recompose very difficult to near impossible at larger apertures. I've seen very similar behavior with the Hexanon 28, though it might be my favorite 28mm option at the moment. I was hopeful about the Elmarit 28 ASPH but it appears to have even more issues - http://blog.kasson.com/?p=6329



Aug 19, 2014 at 10:27 AM
AhamB
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p.1 #6 · p.1 #6 · A7s is great with all RF WA and UWA?


Dustin, thanks for the link to that blog -- quite a wealth of info there.


Aug 19, 2014 at 10:53 AM
Dustobub
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p.1 #7 · p.1 #7 · A7s is great with all RF WA and UWA?


I spent a little time with the Zeiss 25 2.8 Biogon ZM and it is definitely better than the Zeiss 28 regarding color shift and smearing, but it again has a large amount of field curvature on the edges. The Hexanon 28 is still my go to, but I'm a bit bummed in realizing that a perfect 24-28mm rangefinder lens might not happen on the A7S. The search continues...

The whole field curvature issue now has me testing lenses that I felt were near perfect on the A7R - ie. the CV 35 1.2 v2 - and while it has less curvature than the Zeiss 35 C-Biogon, it's definitely still there on the A7S. Wish I still had my A7R for some AB testing as I'm curious if there's any difference in the glass toppings / IR filter. Though it could be that I just never noticed the field curvature on the A7R because I wasn't looking for it...

I spoke with Dan at MaxMax about removing the ICF stack entirely and I'm tempted. This would likely maximize the A7S potential with RF wide lenses, but it would be a big commitment (and not cheap) as you'd need to modify an adapter's thickness to compensate for the focal plane change. There's a chance that the Voigtlander Close Focus adapter could substitute for machining an adapter as it has an infinity adjustment screw, but I don't know if it has enough movement. I might try measuring it this weekend.

To be continued...

-Dustin



Aug 29, 2014 at 12:57 PM
hiepphotog
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p.1 #8 · p.1 #8 · A7s is great with all RF WA and UWA?


Dustobub wrote:
I spent a little time with the Zeiss 25 2.8 Biogon ZM and it is definitely better than the Zeiss 28 regarding color shift and smearing, but it again has a large amount of field curvature on the edges. The Hexanon 28 is still my go to, but I'm a bit bummed in realizing that a perfect 24-28mm rangefinder lens might not happen on the A7S. The search continues...

The whole field curvature issue now has me testing lenses that I felt were near perfect on the A7R - ie. the CV 35 1.2 v2 - and while it has less
...Show more

Dustin, Dan actually offers to move the sensor so you don't need to modify your existing adapter: (beside I think only Hawk's adapter can actually adjust the infinity focus)

https://www.fredmiranda.com/forum/topic/1314208/15#12547219



Aug 29, 2014 at 01:09 PM
edwardkaraa
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p.1 #9 · p.1 #9 · A7s is great with all RF WA and UWA?


hiepphotog wrote:
Dustin, Dan actually offers to move the sensor so you don't need to modify your existing adapter: (beside I think only Hawk's adapter can actually adjust the infinity focus)

https://www.fredmiranda.com/forum/topic/1314208/15#12547219


I didn't keep a copy of the correspondence because I decided to sell my A7 kit ultimately, but I can recall the cost was quite high (also not sure about this one, but I think they told me they had never done any work on the A7 at that time, so it was all theoretical). Just to keep your expectations realistic




Aug 29, 2014 at 01:12 PM
carstenw
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p.1 #10 · p.1 #10 · A7s is great with all RF WA and UWA?


hiepphotog wrote:
Dustin, Dan actually offers to move the sensor so you don't need to modify your existing adapter: (beside I think only Hawk's adapter can actually adjust the infinity focus)

https://www.fredmiranda.com/forum/topic/1314208/15#12547219


That just links back to the Loxia thread. Is there another thread about the sensor topping removal?



Aug 29, 2014 at 01:23 PM
hiepphotog
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p.1 #11 · p.1 #11 · A7s is great with all RF WA and UWA?


carstenw wrote:
That just links back to the Loxia thread. Is there another thread about the sensor topping removal?


I just referred back to the service. As for another thread, I know this user did it without moving his sensor assembly. According to his words, he saw improvement. But his flickr didn't show any hi-res picture taken with such modded camera.

https://www.fredmiranda.com/forum/topic/1299203/1#12395472

I seriously hope to get a better result after going through all these costly conversion. It's still better than to buy the native Leica M to me. Right now, I'm seeing huge field curvature on my RF wide (sadly forward, away from the lens).



Aug 29, 2014 at 01:30 PM
Dustobub
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p.1 #12 · p.1 #12 · A7s is great with all RF WA and UWA?


Dan @MaxMax said he's done a few A7/A7R conversions but hasn't done an A7S yet. He did confirm that the A7 series sensors can't be moved forward so you do need to modify the mount/adapter distance.

The newest Hawks adapter does have infinity focus adjustment, but I believe so does the new Voigtlander adapter. It doesn't really appear to be documented anywhere, but I see two screws surrounding the infinity lock plate, which alludes to it being adjustable.







Aug 29, 2014 at 01:40 PM
hiepphotog
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p.1 #13 · p.1 #13 · A7s is great with all RF WA and UWA?


I think that is just to hold the tab in. The Hawk's has 4 screws at that position (2 to allow adjustment, and 2 to hold the tab).


Aug 29, 2014 at 02:40 PM
Dustobub
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p.1 #14 · p.1 #14 · A7s is great with all RF WA and UWA?


hiepphotog wrote:
I think that is just to hold the tab in. The Hawk's has 4 screws at that position (2 to allow adjustment, and 2 to hold the tab).



Ah! So you're right. Damn. Well the newest Hawks could be an option, but I still don't know if it has enough freedom of adjustment. It'd be much better if the entire sensor mount could be moved, but Dan @MaxMax said it's never been attempted and certainly wouldn't be easy to do.



Sep 09, 2014 at 04:03 PM
sebboh
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p.1 #15 · p.1 #15 · A7s is great with all RF WA and UWA?




Dustobub wrote:
Ah! So you're right. Damn. Well the newest Hawks could be an option, but I still don't know if it has enough freedom of adjustment. It'd be much better if the entire sensor mount could be moved, but Dan @MaxMax said it's never been attempted and certainly wouldn't be easy to do.


seems like it would be easier to move the mount closer to the sensor than move the sensor. that has the added benefit of making the camera a bit smaller too.




Sep 09, 2014 at 04:18 PM
hiepphotog
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p.1 #16 · p.1 #16 · A7s is great with all RF WA and UWA?


sebboh wrote:
seems like it would be easier to move the mount closer to the sensor than move the sensor. that has the added benefit of making the camera a bit smaller too.



But then if we can move the sensor, there is no need for any custom adapter and the native lenses would still be able to achieve infinity (performance might be questionable as noted).



Sep 09, 2014 at 04:24 PM
hiepphotog
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p.1 #17 · p.1 #17 · A7s is great with all RF WA and UWA?


Dustobub wrote:
Ah! So you're right. Damn. Well the newest Hawks could be an option, but I still don't know if it has enough freedom of adjustment. It'd be much better if the entire sensor mount could be moved, but Dan @MaxMax said it's never been attempted and certainly wouldn't be easy to do.


Too bad Dan couldn't give us a rough idea of distance we need to adjust for. Definitely a job for a machinist to mill a custom jig. I would recommend Adam Dau from S.K. Grimes. They have been in the business of machining parts for camera longer than other machinists I came across.

Are you going through with the process? Dan said it's reversible but the cost would be the same. Either way, I'm thinking really hard about it, probably in another month or so.



Sep 09, 2014 at 04:29 PM
Dustobub
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p.1 #18 · p.1 #18 · A7s is great with all RF WA and UWA?


I've now spent some time with three new lenses on the A7s: M-Hexanon 28mm f/2.8, Zeiss 25mm ZM f/2.8, and the very intriguing M-Hexanon Dual 21-35mm f/3.4-4 and I wish I had better news to report. On the upside, there is next to no color cast on all three. However, they all still have significant field curvature at short/medium/long distances.

I was most hopeful of the Dual Hexanon as it's a retrofocal design (by M-mount standards). It really is an incredible piece of glass - extremely well built and with a wonderful feel. It would be a great outdoor walkaround lens for the A7s.

In testing it though I've learned a few interesting things. Nothing not known to others I'm sure, but for me it was a bit of a lightbulb and will force me to retest some other wide lenses on the A7s. In my normal shooting with MF glass and an EVF I set the lens wide open (or one stop down), focus, and then stop down to my desired aperture and shoot. This makes focusing easy and is great for normal shooting. Now with a lens that has strong field curvature in the corners, this technique will likely result in very poor corner sharpness. What I've found is that with a lens sufficiently wide enough (21mm on the Dual Hex is very acceptable, but at 35mm it's not great), you can combat the field curvature with smartly placed DOF. For a subject at infinity, this would mean focusing at the hyperfocal distance for your desired shooting aperture. For a subject closer than infinity, first stop down to shooting aperture and then focus at the shortest acceptable distance where your subject is in focus. This slows down the entire process a bit as focusing is much harder when stopped down, but it does lead to better corner performance.

I am going to take a fresh look at the lenses that are piling up in my apartment to see if any of them can perform decently with this technique. If you're looking for reasonable cross frame performance at larger apertures below 35mm with rangefinder glass outside of the Leica WATE, the A7s probably isn't going to be the Holy Grail you want it to be. However, if you're willing to change your technique and are mainly shooting medium to long distance subjects outdoors, there may be hope.

-Dustin

Edited on Sep 09, 2014 at 09:48 PM · View previous versions



Sep 09, 2014 at 04:37 PM
sebboh
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p.1 #19 · p.1 #19 · A7s is great with all RF WA and UWA?




hiepphotog wrote:
But then if we can move the sensor, there is no need for any custom adapter and the native lenses would still be able to achieve infinity (performance might be questionable as noted).


the same is true with moving the camera mount.



Sep 09, 2014 at 04:51 PM
hiepphotog
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p.1 #20 · p.1 #20 · A7s is great with all RF WA and UWA?


sebboh wrote:
the same is true with moving the camera mount.


I thought by "the mount", you meant the included adapter mount. Moving the camera mount would be the same but I think it would be more difficult since the mount is directly attached to the mag-alloy front frame. Unless, I'm mistaken. The sensor assembly, on the other hand, was mounted one several small pegs with shims to ensure proper placement.



Sep 09, 2014 at 05:36 PM
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