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S2-70mm Brick Wall Test

Following the recent discussions in the "more fun images" thread and particularly Thomas's comments regarding corner sharpness I decided to shoot a brick wall and see what happens.

Test setup:
*Leica S2 with 70mm Summarit mounted on a Gitzo 1325 tripod with RRS BH-55 head.
*Camera to wall distance was approximately 2.8 meters.
*There is no easy way to ensure the camera sensor plane is exactly parallel to the wall so I did my best and quit worrying about it.
*Autofocus was used just prior to first photo and was not changed for subsequent shots (I know one should use focus bracketing for a lens test, but I didn't want to bother as I wanted to see how accurate the autofocus was because that is how I use the camera - not focus bracketing)
*Shot tethered to MacBook Pro using Leica's Shuttle software
*Raw conversion in LR 3 Beta 2 using defaults with the only adjustment being my standard sharpening (amount - 50; radius - 0.7; detail 35). I made no attempt to white balance or equalize exposures. Note: I think the variation in corner colors are representative of the actual scene because the wall was under an awning and there was a color temperature variation from top (more shade) to bottom (brighter due to reflection off sidewalk).

I know some or many will find faults with my test method and that is OK. It tells me what I wanted to know and I am happy.

First the full image f2.5



Next a center crop f2.5



Top Left corner f2.5



Top Right corner f2.5



Bottom Left corner f2.5



Bottom Right corner f2.5

 
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Guy Mancuso

Administrator, Instructor
Some distortion and slightly soft in corners and a little light falloff as expected but lens is not at any fault here. Looks normal for a standard lens wide open. Little surprised to see barrel though.

I think you lens and sensor look fine though Mark
 
Hey Guy, I also noticed what looks like barrel distortion, but I am not sure it is. I was alone when I took the photos so there was no way to pull a string to check it out for sure. I suspect a bit of optical illusion with the top brick row - actually excess mortar in the center area of that row. Of course it really could be barrel distortion.

I think the corners look very good considering the lens is wide open at f2.5.
 

Guy Mancuso

Administrator, Instructor
Yea not bad your going to get some falloff in the corners. You can actually see a glow sort of in the middle but this is pretty typical wide open. My bet F4 it cleans up pretty well. Nothing to sweat about in my book. I do think there is barrel i see it in the bottom as well the first 3 rows going up. I do find this surprising since leica claims lens corrections built in. One reason i take any marketing with a grain of salt from anyone.
 

tjv

Active member
Looks like slight barrel distortion but nothing objectionable at all. Totally normal.
Also, compared to most lenses, the corner sharpness is fine for f2.5. I guess one could argue the whole price point thing, but what's the point. As long as people are convinced it will perform well on the next iteration of the S system which I assume will be at least 50mp.

It's all interesting for me though, especially as I begin to embark on the MF digi journey myself. Gotta know what each system component can do.
 

thomas

New member
Mark, many thanks!
Looks really good!

Actually I would have liked to see something at a wide distance (infinity)... but I know that such large brickwalls are rare :rolleyes:
 

David K

Workshop Member
Pretty effective test IMHO as it takes so many variables out of the equation that were present in the other photo. Now go enjoy your new MF kit !!!
 

Jack

Sr. Administrator
Staff member
Pretty effective test IMHO as it takes so many variables out of the equation that were present in the other photo. Now go enjoy your new MF kit !!!
Takes enough variables out to lead us to believe that there is something amiss with the other person's camera or lens --- unless it is a distance-related issue as Thomas suggested. I too would *really* like to see the same type of shot taken from a much longer focus distance. Doesn't have to a brick wall either, a row of tall buildings 30 meters away would suffice for me...
 

Guy Mancuso

Administrator, Instructor
Mark for comparisons sake I shot this test on the Salton Sea workshop with the P40+ and 80mm D lens. Full frame this is without using the correction tools and presharpen 1 which i always use only a little less. About 40 feet away



Center Image 1200 pixels square at 100 percent


Bottom left. Use the brick for comparisons since the wood is obviously closer. Also be careful the wall is split here and falling left


Bottom right again use the wall itself
 

Guy Mancuso

Administrator, Instructor
Pretty typical again wide open slightly softer in corners and a little fall off. Distortion is hard to tell here because the wall is obviously not as square as we would want but it seems pretty good. Obviously this is all at 2.8

Not so sure I am totally square either seems I am left side down to start. I could do this again to check distortion if you wanted to see that.
 

Guy Mancuso

Administrator, Instructor
I do agree with others though that your system is fine to go for sure and what we see from your tests is pretty normal. That other kit as we have seen something seems seriously amiss.
 

Bob

Administrator
Staff member
Pretty typical again wide open slightly softer in corners and a little fall off. Distortion is hard to tell here because the wall is obviously not as square as we would want but it seems pretty good. Obviously this is all at 2.8

Not so sure I am totally square either seems I am left side down to start. I could do this again to check distortion if you wanted to see that.
Guy,
WTF? your upper corners are black LOL
 

thomas

New member
unless it is a distance-related issue as Thomas suggested.
Hi Jack,
I don't know if there may be distance related issues... I only know that lenses mostly look relatively good at close distances (unless it's almost near limit, of course) whereas things look a bit different at wider distances.

In any case: I didn't want to spoil the party!!!
It's just something I've noticed when looking at the S2/70mm images availabe. As corner sharpness and an even spread of DOF is quite important for me personally this is something I am looking at automatically - here... http://tashley1.zenfolio.com/p627107524/h2eb5b8e2#h2eb5b8e2 ... it simply looks strange to me that sharpness at the edges is okay in the forground but the wider the distance the more the falloff from the center of the image to the edges is noticable (in the plane of the orange cranes the center is still within DOF but the edges are clearly soft). I think at f6.7 or f8 it should look more even.
 

Jack

Sr. Administrator
Staff member
Exactly. Lenses are optimized for a single focus distance --- actually magnification factor --- usually this is around 1:10 for "normal" lenses, 1:1 or 1:2 for macros. However some manufacturers choose to optimize their glass for closer distances, so you can find 1:6 or 1:8 also. I suspect based on their "street" legacy, Leica chose something closer for the S lenses like 1:8. This isn't bad or good, just a choice. But it may also mean more icky optical stuff starts to happen as you move further away from that optimal point, like towards infinity...
 

gogopix

Subscriber
Thanks Mark
Such a simple test clarifies a lot. So, the 70mm is a good, but maybe not a great lens? We usually don't look at brick walls.

In the other thread, sharpening issues aside, xpixel's images have a look that IS special. Whether it can be duplicated with other systems and processing is sort of moot; Leica goes for aesthetics, which some like, some don't.

But if you see and like, you will want - then like Ben and Jerry's vs xyz ice cream if you want, you will pay the price.

Victor

PS The vaunted 40mm Zeiss IF lens, the 21mm 2.8 the 35-70 Leica R all had some issue; distortion, focus shift, soft corners (sometimes) but these lenses just has a special something (Col Sanders would LOVE them )
Same with cameras, the DMR and now M9 have a color and depth that you can't buy back with resolution. SO ok, not thye best ISO or fps.

In the end, for a subset of the market they will see (maybe) a special charater to the S2 and $24k is, well, it is what it is.
 

Guy Mancuso

Administrator, Instructor
M,R,S all different lens designs. One does not mean the other is the same. Need to remember this and the S lenses are all based on the same design and are all called summarits. M has maybe 6 different styles as well as the R glass. The S has one style. We all know in either a M or R a lux is totally different than a cron for instance. I said this from the day they announced the S2 . Not that they are bad but they will look the same through the line. Unfortunately MF does not have a lot of styles of glass except picking up some legacy stuff that can give you a different look.
 

gogopix

Subscriber
The well known Leica expert, Ken R. says;

"Leica's trademarks tell you nothing about the lens' design, its age or its history. To refer to a 90mm Summicron means nothing more than to refer to a Leica 90mm f/2 lens. Leica has made at least three totally different 90mm f/2 optical designs housed inside many cosmetically different barrels over the past fifty years, all called Summicron. "

Does that mean all S lenses are 2.5? (wow, even a 350mm?
Actaully ZEISS names like Planar and Sonnar did mean design types.

If Guy is right then Leica has found a way to standardize on both an aperture and design. Can't see it in the 35 to 350mm rage. There have GOT to be design differences.

Victor
 

Jack

Sr. Administrator
Staff member
Victor,

Put us and yourself out of misery, and just go frigging buy one already!

Then get a room.

:D

(Seriously, it's a very sweet camera and I'm sure you will enjoy it a lot.)
 
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