APO Summicron 75/2 (for Sony FE mount)

[Vivek]

Jonas asked in another thread:

Hi Vivek,
If you have the time: I would appreciate if you elaborated a little about the M 75/2 AA. How much APO is it? Is there any field curvature to worry about? How is background and foreground bokeh if compared (I'm interested in background bokeh only.)
I ask as I like the focal length and the Voigtländer 75mm is anything but APO... and I'm contemplating looking for the AA75 or the Lux-R 80mm. Any comments are appreciated.

I thought I will start a separate discussion here to unclutter the other thread.

The lens with the adapter ("K&F Concept" from China) with a self cobbled APO Componon 60/4 and an adapter mounted Contax G 90/2.8. All lenses have proper lens hoods fully deployed.

As is apparent, the size of the AA 75/2 is just "perfect".

How the lenses look from the rear (what the sensor sees):

The APO Componon and the Contax lenses look fine due to proper shields (no shiny bits). The AA 75/2 shows that shiny metal that Leica are so proudly showing of as the best feature of their fine cameras ROTFL like Leica T.

It does not look bad.

Upclose when the lens is focused away from infinity:

More of that machine work is shown off to the sensor.

The lens (optics) is superb but that shiny metal innards are a problem when used like this. If someone is going to use the lens exclusively for Sony E and want the best out of it, then it needs a lit bit of work to shield those glistening metal parts.

How APO is APO? That is a not a simple question.

The APO Componon (aka, APO Makro Componon, Macro Digitar, APO Macro Digitar) is a good lens. If that is taken as a reference, the AA 75/2 is a bit more APO than that.

The AA 75/2 bleeds a bit of long wave UV but is of NO concern on an A7r and such since their sensors see 0% UV. Film folks were not too thrilled with this lens or its bokeh (unlike the fuzzy smooth Mandler lenses) but AFIAC, it is just superb on digital (especially Sony A7r). The built lenshood is awesome. One can use ND filters (I do) with beneficial results.

I have posted many pictures using this lens on A7r here. I don't do any side by side comparisons.

 

[Jonas]

Hi Vivek,
...and thanks for the comments on the 75mm AA. I think the APO question is impossible to answer but you did anyway, in a way.
I'll go check out images by you and whatever I can find.
Thanks again!

 

[Vivek]

You are welcome, Jonas! I really like this lens despite all the shortcomings I listed.

Here is one of the earliest snaps I made with it. Most likely f/2 or f/2.8, handheld, A7r, under the typical overcast sky here.

 

[Jack]

In general, how do Contax G lenses hold up over the A7r sensor?

 

[Mark Muse]

Vivek, you might know this, but the Fotodiox Pro adapter for the Zeiss G lenses have some advantages over the Metabones adapter, in my opinion. They are significantly lighter, they are a little easier to mount the lenses, and they focus a little more smoothly. For the life of me, I don't know how Metabones got the good rep that have.

 

[Vivek]

In general, how do Contax G lenses hold up over the A7r sensor?

Jack, Carl probably knows the best along with Slingers (who has every G lens). I only have the 90/2.8 and it is stellar (IQ) but a bit too contrasty to my taste.

I think the G 90/2.8 can handle even the rumored A9.

 

[Vivek]

Vivek, you might know this, but the Fotodiox Pro adapter for the Zeiss G lenses have some advantages over the Metabones adapter, in my opinion. They are significantly lighter, they are a little easier to mount the lenses, and they focus a little more smoothly. For the life of me, I don't know how Metabones got the good rep that have.

Thanks, Mark. I just bought this as a set so there it is (and they are always together). If I start using the G 90/2.8 a lot, I will get the Fotodiox adapter.

 

[Jack]

Thanks Vivek, that answers it -- older Z designs were always a little heavy on contrast for my tastes. I am awaiting the Sony 28, and hope it it is stellar. If not, I may just opt for a 24-70 and call it done.

 

[Jonas]

Here is one of the earliest snaps I made with it. Most likely f/2 or f/2.8, handheld, A7r, under the typical overcast sky here.
(image)

He is getting older, no...
I think that must have been f/2.8 - or I would have expected some more separation between your son and the green stuff. Or 75 isn't as long as I think it is together with the image size of course.
Looks good. I have checked a ton of images at flickr and there isn't much to say about the lens. It just seem very good. Not as APO as the best ones perhaps but still good.
So maybe this is a lens I'll look for when I sell the RX1 and go back to the A(x) again. (I had the A7 for a short time, didn't like the ergonomics of it, couldn't make friends with it and always grabbed the RX1. I also didn't find a good 35mm lens for the A7.)

 

[Vivek]

Jonas, One of those rare occasions where a shirt (albeit casual) is worn has to be captured and cherished.

I don't think the 75/2 does great with foliage (bokeh wise) but is divine for street. I can't provide any tripod mounted examples with careful comparisons as I never would use it like that.

Here is one at f/2. It is very APO as APO goes, especially for FF.

Untitled by Vivek Iyer, on Flickr
A7r, AA Summicron 75/2, The Hague

 

[Annna T]

Thanks Vivek, that answers it -- older Z designs were always a little heavy on contrast for my tastes. I am awaiting the Sony 28, and hope it it is stellar. If not, I may just opt for a 24-70 and call it done.

They have a lot of microcontrast. The 45mm F2 is even sharper than the 90mm. The bokey is rather busy, those lenses are made for those who like sharpness, not bokey. Think "neue Sachlichkeit"

I never had the 35mm but at the time it was said to be inferior to the 45mm and a little deceiving.

The 28mm and 21mm both F2.8 are symmetrical Biogon designs and suffer from smeared corners, vignetting etc.. Just like other wide RF lenses. The 21mm has to be slightly modified to be fitted on E-mount. It was a superb lens for film, low distorsion and incredibly sharp. A dream for architecture.. But alas quite useless on the A7r.

All these Contax G lenses tend to show up purple fringing in backlight situations. In fact it is the only thing I didn't like on the A7r. Since I have got the 55mm FE, I prefer to use that lens over the Contax G lenses.

One added advantage of the Contax G lenses is that they are also both light and compact (none weight more than 200gr). They are perfect companions to the A7r.

One thing I have noted is that compared to more recent "made for digital" lenses, their optimum sharpness lies about one stop lower (like F8 instead of F5.6).

 

[Jack]

Nice summary Anna, thank you! :thumbs:

 

[Vivek]

All these Contax G lenses tend to show up purple fringing in backlight situations. In fact it is the only thing I didn't like on the A7r. Since I have got the 55mm FE, I prefer to use that lens over the Contax G lenses.

I am curious about both those statements. Can you show some examples where you have seen this purple fringing? How one lens (Sony/Zeiss 55/1.8) replaced all those G lenses?

 

[serhan]

Anna summarized it pretty good. Not to divert from here I posted my shots in another thread:
http://www.getdpi.com/forum/sony/53044-contax-g-45mm-a7r.html#post619092

From what I read, contax g 45mm is similar to ZM 50mm planar. I find contax g lenses less contrasty to latest Zeiss lenses. g35mm is not that sharp wide open as g45mm but it is not bad stopped down eg check the loxia 35mm review:
Zeiss Loxia Biogon 35/2 Review | Viktor's photo blog - Part 2

To make it even more complicated I added also one Planar in the mix. Contax G Zeiss Planar 45/2 is one of the best standard lenses ever made. 35/2 is not as good, but it is the smallest and cheapest lens in this comparison, while still carrying Zeiss signature. Stopped dow to f/5.6 it is as sharp as I would ever need, so it definitely should be considered.

 

[philip_pj]

The Sony 28mm will be a 'G' lens (good?), down a step from 'ZA' (Zeiss-inspired Sony manufacture). Sony have released a lot of zooms and now G macro and G 28 plus a converter, for the incoming DSLR types.

Anyone who loves the look of old Zeiss - which in CY form are now very popular with cinematographers for their beautiful filmic rendering, smooth but detail retaining bokeh, and microcontrast - might look into either the CY 85/2.8 or 100/3.5 - both are stronger than the G90 and are around 280 grams.

The 100 is as strong as the FE55, with fine OOF at f3.5 and a near unique MTF wide open. On a7r that is. Very similar lenses, wonderful corners. Most high prod value TV series and anything made by Fincher will look very familiar to CY lens users. Agree re f8 is optimal, Zeiss were more interested in controlling curvature than Leica for infinity work, for open field imagery.

The 75AA is rather similar at f2 to the 100mm in MTF then loses its way with some midfield curvature at f2.8 before getting straight by f5.6. The 100MP is even better/flatter than my 100/3.5 but weighs like a boat anchor!

 

[MGrayson]

Here are some soulless measurements to brighten your day. :lecture: I've been trying to quantify just how good or bad of old glass is on the A7II.

The 75 Cron is very sharp in the center wide open with a gentle rolloff to the edges. At f/5.6, it is sharp across the frame. This is measured on an A7II. The lower surface is at f/2.0, the upper at f/5.6. The x and y axes are position on the sensor. The z axis is line pairs per mm at MTF 50 (higher is sharper).

In contrast to the 50 Lux pre-ASPH, which is much softer everywhere wide open (lower surface is at f/1.4):

These plots are consistent with the MTF charts in the Erwin Puts book, so this isn't an A7 vs. M9 issue.

The DoF is just as shallow on the 75 Cron as on the 50 Lux. I don't much shoot 50mm anyway.

Best,

Matt

Edit: Plots are better now, with any shots taken to get the best focus data. Not much field curvature at this (close) distance, as the sharpest results were usually from one or two frames.

 

[Annna T]

I am curious about both those statements. Can you show some examples where you have seen this purple fringing? How one lens (Sony/Zeiss 55/1.8) replaced all those G lenses?

As a former Contax G2 user, I do still have the 90mm F2.8, the 45mm F2, the 28mm F2.8, the 21mm F2.8 and the 16mm F8. The 16mm can't be mounted on the E mount bodies because the rear part is sticking out too far. On the 21mm you have to cut two plastic little wings that stick too far into the body. I didn't make it because Carl Scho who has done it confirmed that it produced bad corners, so not worse the trouble. Same bad corners for the 28mm. I don't have the 35mm. So remains the 45mm and the 90mm. They are both rather difficult to focus, since my TechArt adapter is a little tricky. Since I have the 55FE which is an incredible performer, i don't use the 45mm that much. As for the 90mm, I prefer to use the Tamron SP 90mm F2.8 macro (first old version without stabilisation) with Canon mount on the Metabones Smart adapter : it is easier to focus than the Zeiss Contax G with the Techart adapter (which is hit and miss).

As for purple fringing, I have too much disorder in my files to bring you one out on the spot. I was already getting it when scanning the negs of the Contax G2 films and constated that on the A7r, in the typical situation where fringing occurs, these Zeiss lenses were producing a wider fringe than actual lenses. That's all. It isn't to say that the lenses aren't usable. It was just the report of something I have noted.

 

[Jonas]

Here are some soulless measurements to brighten your day. :lecture: I've been trying to quantify just how good or bad of old glass is on the A7II.

The 75 Cron is very sharp in the center wide open with a gentle rolloff to the edges. At f/5.6, it is sharp across the frame. This is measured on an A7II.
(...)

Hi Matt,

Here is the MTF from the Leica "Technical Data" -brochure:

The Leica MTF is calculated and at infinity. The Lenstip review shows data similar to yours (and they used an M9). So, I wonder what's up? Do we see the result from field curvature at short distances?
(I don't have Erwin's book but aren't the MTF curves in his books and articles the same as theose published by Leica?)

 

[MGrayson]

Jonas,

I was only comparing Puts' 50 Lux pre-ASPH, as that data isn't on the Leica website anymore. The pdf of his book that I have doesn't even have the 75 Cron - it's too new.

As far as the 75 Cron results, I'm assuming those are the 5, 10, 20, and 40 lp/mm curves in the published chart? (Just checked: yep, they are.) If so, then the wide open MTF50 surface should lie almost entirely above 40 lp/mm level.

I have no good ideas, having just recently moved from pixel-peeping to full on measurebating :ROTFL:. But it could be sample variation, close distance vs. infinity, or calculated vs. measured. Puts says that there is no difference in the latter case (hmmmm...). If Lenstip didn't agree, I'd just chalk it up to my own inexperience. But as Roger Cicala says: Measuring lenses is hard. If I remember his advice correctly, it's that a home setup is only good for detecting gross decentering, not sharpness evaluation.

Best,

Matt

 

[Jonas]

Hi Matt,

Yes, Leica publishes results for 5, 10, 20 and 40 lp/mm and I understand your plots shows the result as lp/mm at MTF50, no?
The big question for me is if I can take a sharp image of a plane target (art, graffiti, a building). I'm worried about Leica field curvature since my Summilux-M 35/1.4 couldn't do that for its life, at any aperture really.
So, with the full image under the loupe - how much would I need to stop down to get an image sharp corner to corner at say 3-4 meters (or yards?) distance? Have you taken any such images? I don't doubt the lens' capabilities when it comes to center "sharpness" for portraits and similar images.
Cheers,
Jonas