Zeiss: on MTF, their 85mm f/1.4 ZAlpha mount lens, the Sony Alpha DSLR-A900 camera, and more

peterblaise · April 6, 2009

.

I've been reading recent Zeiss white papers on MTF, their Zeiss 85mm f/1.4 ZAlpha mount lens, the Sony Alpha DSLR-A900 camera, and more, and I want to share the links with you and see if you also find them informative and provocative.

Zeiss Camera Lens News 30 and 31:

"... In the first part of this article ... Dr. Hubert Nasse, Senior Scientist of the Carl Zeiss AG, gave an answer to the question “Why do we need MTF curves?” ... the shape of the point images as determined by the aberrations and diffraction on the one hand correlates with the modulation transfer on the other ... look at different motifs each of which were imaged using twelve different transfer functions ... available for you to download from our server. The PDF includes the MTF curves relating to the images as well as additional explanations ... Please read on here in order to disclose more secrets around MTF curves ... "

How to read MTF charts - Part 1:

<a href="http://www.zeiss.com/C12567A8003B58B9/ContentsWWWIntern/D9A30A166F326924C125751A004AB770">http://www.zeiss.com/C12567A8003B58B9/ContentsWWWIntern/D9A30A166F326924C125751A004AB770</a>

Measuring lenses objectively – Part 2:

<a href="http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_31_MTF_en/$File/CLN_MTF_Kurven_2_en.pdf">http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_31_MTF_en/$File/CLN_MTF_Kurven_2_en.pdf</a>

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild1/$File/Image_01.jpg" target="_blank">Image 1</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild1/$File/Image_01.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild1/$File/Image_01.jpg</a> (4.87 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_02.jpg" target="_blank">Image 2</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_02.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild2/$File/Image_02.jpg</a> (3.76 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild3/$File/Image_03.jpg" target="_blank">Image 3</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild3/$File/Image_03.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild3/$File/Image_03.jpg</a> (0.85 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild4/$File/Bild_04.jpg" target="_blank">Image 4</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild4/$File/Bild_04.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild4/$File/Bild_04.jpg</a> (1.29 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild5/$File/Bild_05.jpg" target="_blank">Image 5</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild5/$File/Bild_05.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild5/$File/Bild_05.jpg</a> (0.84 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild6/$File/Bild_06.jpg" target="_blank">Image 6</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild6/$File/Bild_06.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild6/$File/Bild_06.jpg</a> (0.4 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild7/$File/Bild_07.jpg" target="_blank">Image 7</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild7/$File/Bild_07.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild7/$File/Bild_07.jpg</a> (1.66 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild8/$File/Bild_08.jpg" target="_blank">Image 8</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild8/$File/Bild_08.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild8/$File/Bild_08.jpg</a> (1.91 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild9/$File/Bild_09.jpg" target="_blank">Image 9</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild9/$File/Bild_09.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild9/$File/Bild_09.jpg</a> (1.79 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild10/$File/Bild_10.jpg" target="_blank">Image 10</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild10/$File/Bild_10.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild10/$File/Bild_10.jpg</a> (2.16 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild11/$File/Bild_11.jpg" target="_blank">Image 11</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild11/$File/Bild_11.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild11/$File/Bild_11.jpg</a> (3.12 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild12/$File/Bild_12.jpg" target="_blank">Image 12</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild12/$File/Bild_12.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild12/$File/Bild_12.jpg</a> (4.23 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild13/$File/Bild_13.jpg" target="_blank">Image 13</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild13/$File/Bild_13.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild13/$File/Bild_13.jpg</a> (1.1 MB)

<a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild14/$File/Bild_14.jpg" target="_blank">Image 14</a> <a href="http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild14/$File/Bild_14.jpg">http://www.zeiss.com/C12567A8003B8B6F/GraphikTitelIntern/CLN31MTF-KurvenBild14/$File/Bild_14.jpg</a> (0.43 MB)

</blockquote>

----------

Here are some insights I had so far:

<ul>

<li>- MTF is waay to complex to simplify down to one number, let alone to compare different people's MTF reports</li>

</ul>

<ul>

<li>- MTF reports en mass can assist a lens designer in understanding what they have done and what happens when they make changes</li>

</ul>

<ul>

<li>- current top-of-the-line lenses can resolve to about 1/4 the point size resolvable by current top-of-the-line cameras</li>

</ul>

<ul>

<li>- MTF is different when the same lens is tested on film versus digital, and MTF is different when tested on different digital cameras</li>

</ul>

<ul>

<li>- SQF is scientific and meaningful, but means something other then visually equivalent results for lenses with equivalent SQF numbers</li>

</ul>

<ul>

<li>- realistic print viewing distance for pleasure is more important than 1:1 100% screen inspection close up (Duh!)</li>

</ul>

<ul>

<li>- some lenses may perform better on digital than on film, MTF wise, and better on one digital camera than on another, including some counter intuitive results</li>

</ul>

<ul>

<li>- the Zeiss 85mm f/1.4 lens in Alpha Mount has a symmetrical MTF for subject scene objects on either side of the focus plane, near and far, rendering smooth bokeh </li>

</ul>

<ul>

<li>- more pixels, please - 1 micron pixels would be nice in a full frame camera (can you say "TERApixel DSLR?)! </li>

</ul>

<ul>

<li>- Adobe and Luminous Landscape and DxOMark are stealing the photographic community's attention, so Zeiss probably should be more in the public eye, and Zeiss should publish more white papers</li>

</ul>

<ul>

<li>- German to English translations are a challenge, and the pages read across columns first, then down the page</li>

</ul>

<ul>

<li>- Raw nicely processed from a smaller resolution camera can beat JPG from a higher resolution camera (Duh!)</li>

</ul>

<ul>

<li>- Raw from a higher resolution camera can probably be processed quite well (Double Duh!) </li>

</ul>

<ul>

<li>- Zeiss hates Raw, and color management, too, and would like to not think about either of them at all</li>

</ul>

I will respond more as I re-read the white papers above, and report back here with my notes. Enjoy!

.

bill_tuthill · April 7, 2009

Realistic print viewing distance for pleasure is more important than 1:1 100% screen inspection close up (Duh!)

I would say "Baloney" instead of Duh. Nobody with a digital camera prints all their pictures now. Photographs have become something that you attach to an email. If a picture doesn't look good on screen, it doesn't matter how well it prints – nobody will select it for printing.

peterblaise · April 8, 2009

.

Excellent observation, Bill. One reason Ritz tanked is that people weren't just printing at nome, but people weren't printing at all! However, inspecting at 1:1 100%? What for?

Regardless, that's (one little tiny bit of) MY take on the Zeiss exploration, and maybe I'm reading into it something you would interpret differently? Did anything in the Zeiss reports newly inform or stimulate your insight into what's meaningful and useful technology wise with our gear offering out there today?

.

robert_paul1 · April 9, 2009

Speaking of lenses, my all time favorite lens is the Minolta 58mm f/1.2. I've always wondered why Minolta came out with a 58mm, and not a 50mm, but I've never been able find out why. It was because of this lens that I bought my first SRT101, which was agreat camera.

peterblaise · April 9, 2009

.

Wow, we have something in common after all! I LOVE my own:

<ul>

<li>1968 Minolta Rokkor-PG 58mm f/1.2 MC SR mount (7 elements in 5 groups) 475 grams</li>

</ul>

... in 1973 they made an all black model a little lighter, originally ~$395. Which model do you have -- silver or black?

----------

In re-reading the Zeiss white paper, I see I misunderstood the symmetrically appearing MTF charts for the Zeiss 85mm f/1.4 Alpha Mount. Here's how they describe it (though it DOES look symmetrical):

Part II, page 12:

... Lenses with spherical under-correction, which is felt to be more pleasant, have a flat MTF curve in the background and a steeper MTF curve in the foreground. This is evident from the following focus MTF curve of the Planar 1.4/85 ZA ...

</blockquote>

Regardless, it appears they care about bokeh. Color awareness a la Minolta heritage, however, seems out.

.

robert_paul1 · April 9, 2009

Yes, but why did Minolta make it a 58mm?

ricardovaste · April 9, 2009

I've always wondered why Minolta came out with a 58mm, and not a 50mm

</blockquote>

I think I recall hearing somewhere that it had something to do with the viewfinders on the SR-T's. Something like the 58mm FOV matching up with the magnification of the VF? So that when you look through the lens with one eye, the image in the VF will match that with the other eye out of the VF - making composition/focusing an easier process. But my memory is poor, and details often blur ;-).

I've used a couple of Rokkor 58/1.2's (sold my first for financial reasons). I bought a second because I didn't feel I had enough time to really grasp the first one properly. However, I do feel it's over-rated a little... from how some people speak of it atleast (not yourself).

Bought a Minolta 85/1.4 a month or so ago. I haven't had much change to use it at all, and when I have I've found it quite challenging to get anything decent from it at all. However, got one shot yesterday which I'm happy with because I think I'm starting to get a 'feel' for it now.

<img src="http://gallery.photo.net/photo/8934591-md.jpg " alt="" width="679" height="979" /> A700, MinO85/1.4, ISO200 - B&W in CS4*

*The conversion is something I've been experimenting with the last couple of days. Kind of a mixture of 'digital lith' effect and duo-tone effect.

The Minolta 85/1.4 definately doesn't have the wide open sharpness of the ZA, nor the micro-contrast... but for the kind of portraits I like to take I think the lower-contrast, sometimes 'softer' look suits me more.

drjedsmith · April 9, 2009

Rich, great showing for that Minolta 85mm, and that shot with conversion looks really great. I mean that - you know I don't hand out compliments often on the 'net for digital photography, either. :-)

I like the way your style is evolving. Keep it up, my friend!

Greetings from across the pond,

Dr. Smith

peterblaise · April 9, 2009

.

Richard, read the Zeiss white papers regarding why your 1987 Minolta 85mm f/1.4 Alpha Mount lens (7 elements in 6 groups, many versions) may not be "as bad" as you think. New point I've culled from my reading (many more to come):

<ul>

<li>Any imaging system is not as weak as it's weakest link as much as it's as strong as it's strongest link, that is, a cheap lens on an expensive sensor may return more information than an expensive lens on a cheap sensor (paraphrase, Part II, page 27).</li>

</ul>

There is so much more I am gleaning form Zeiss's sharing ... read 'em and please report what you get form them -- thanks!

----------

Robert, we all speculate why 58mm, but I suspect it was to show Minolta had the widest offering (though Pentax also had and has some odd focal lengths), helping distinguish Minolta uniquely as a glass maker as well as a lens retailer. So, Minolta has 50mm f/1.2 and 58mm f/1.2 in SR mounts. 55mm oddly was f/1.7 or f/1.8. They had f/1.4 from 35mm to 85mm. They had f/2 from 28mm to 135mm. They also has an 18mm f/9.5 and mirrors up to 1,600mm f/11 at the other end of the maximum aperture range. But, more importantly to me, they had f/1.2 zooms ... for their 8mm movie cameras -- WOW! Only From The Mind Of Minolta . Why? Because they can, er, or could .

Mathematically, perhaps someone can find old owner's instruction manuals that extol the virtues of 58mm as a specific magnification for head shots or full body shots from specific distances, as the old owner's instruction manuals often showed examples of Minolta cameras used for such purposes. Who can find authoritative references? David Kilpatrick?

----------

Again, here are the Zeiss PDFs:

<ul>

<li>How to read MTF curves Part I: </li>

</ul>

<ul>

<li><a href="http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_30_MTF_en/$File/CLN_MTF_Kurven_EN.pdf">http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_30_MTF_en/$File/CLN_MTF_Kurven_EN.pdf</a> </li>

</ul>

<ul>

<li>How to see MTF curves in images Part II: </li>

</ul>

<ul>

<li><a rel="nofollow" href="http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_31_MTF_en/$File/CLN_MTF_Kurven_2_en.pdf" target="_blank">http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_31_MTF_en/$File/CLN_MTF_Kurven_2_en.pdf</a> </li>

</ul>

.

robert_paul1 · April 9, 2009

Richard, I liked to use my 58mm in the late afternoon, and capturing images when the light was fading. Back then, it wasn't so much about how sharp the lens was, like it is today.

Peter, when I bought my SRT-101 with the 58mm f/1.2, they didn't have the 50mm version, that was sevral years off. I think Richard's explanation makes more sense.

peterblaise · April 10, 2009

.

<ul>

<li>OT / Off Topic: </li>

</ul>

Yes, I like NOT FOV but magnification through the viewfinder to be equivalent so I can shoot with both eyes open. Is it your experience that the 1966 Minolta SR T 101 SR Mount camera viewfinder and the 1968 Minolta Rokkor-PG 58mm f/1.2 MC SR mount lens combine to make 1:1 100% (non)magnification of the view (at infinity)?

How about on any other camera, folks -- what focal length best matches the viewfinder on your other cameras this way, for 1:1 view with or without the camera to your eye? On my current daily favorite 2003 Minolta DiMage A1 DSL/EVF it's ~100mm equivalent (~25mm actual). Is there a science to this or do we go by "feel"?

</blockquote>

.

User_502260 · April 11, 2009

Minolta wasn't the only company to have a standard lens which was longer than 50mm. My first standard SLR lens was the 57/1.4 Konica Hexanon. When camera makers went from RF cameras to SLR cameras they found it difficult to make lenses a short as 50mm which gave correct viewfinder magnification and also allowed the mirror to clear the rear of the lens. This was less of a problem with the slower lenses. When I had the 57/1.4 Konica also had a 52/1.8 but the f/1.2 lens was also a 57. By 1975 I had worn out both my Autoreflex T2 and the 57/1.4 lens. I traded them for an Autoreflex T3 and the newer 50/1.4 Hexanon lens. The new lens was a seven element design and was at least as sharp as the old 57. I have many examples of the 57/1.4 in my collection now but only one first-version 50/1.4. The first version of the 57/1.2 had chrome & black colors and the EE lock pin. The coating was improved in the last model and rubber was added to the focusing ring but the 57mm focal length and the optical formula remained the same. I don't think Konica sold enough of these to make reformulating the lens worthwhile.

Some other longer-than-50 lenses I have include the 55/1.4 Mamiya Sekor, 58/1.4 Minolta MC, 55/1.7 Minolta MC, 55/1.2 Canon FL, 55/1.8 Super Takumar, S-M-C-T, SMC, 55/1.8 SMC Pentax. It's odd about Pentax. They gave up on f/1.4 standard lenses a long time ago but kept a 55/1.8 all the way up to the early K mount era. The one advantage I can think of with lenses 55mm or longer is that distortion was sometimes lower than with a 50. I would like to get a 58/1.2 Canon FL, a 58/1.4 Nikkor, a 58/1.2 Noct Nikkor and maybe a 55/1.2 Canon AL. For Minolta I think I'd rather have the 50/1.2 MD than any of the versions of the 58/1.8. Konica actually made a 52/1.4 in F mount but went up to 57mm when the Auto Reflex came out in 1965. I'm not sure why they did that. The other odd thing about Pentax (Asahi) is that although they had some 50+mm standard lenses for their early SLR cameras, they did not make RF cameras before that.

ricardovaste · April 12, 2009

Rich, great showing for that Minolta 85mm, and that shot with conversion looks really great. I mean that - you know I don't hand out compliments often on the 'net for digital photography, either. :-) I like the way your style is evolving. Keep it up, my friend! Greetings from across the pond, Dr. Smith

</blockquote>

Thanks for the encouragement Jed - means a lot to get complimented by you :). Certainly makes the the price of the lens easier to swallow too ;) - I'm starting to really like that shot infact, it has to be printed I think (later this week)... but like ever, when you get one or two shots that are special to yourself (usually on a personal level like the one I posted), the cost of the item suddenly vanishes.

Richard, read the Zeiss white papers regarding why your 1987 Minolta 85mm f/1.4 Alpha Mount lens (7 elements in 6 groups, many versions) may not be "as bad" as you think.

</blockquote>

Never thought it was 'bad' - far from it. I realise it's one of the most well regarded lenses Minolta ever made - just struggling to adjust to it is all. But in honesty, I haven't really put much time into using it yet.

Any imaging system is not as weak as it's weakest link as much as it's as strong as it's strongest link, that is, a cheap lens on an expensive sensor may return more information than an expensive lens on a cheap sensor (paraphrase, Part II, page 27).

</blockquote>

'More information' isn't really what we get out of a successful shot though sadly ;). It's no secret that you can put any decent old lens on a camera like the A900, stop it down to f/8-f/11 and get sharp pictures from it... but you're not going to exploit the sensor and most people buying such a camera are in it for the sensor.

Richard, I liked to use my 58mm in the late afternoon, and capturing images when the light was fading. Back then, it wasn't so much about how sharp the lens was, like it is today.

</blockquote>

That's how I used it when I had it. However, I don't agree that it's about how sharp it is nowadays. From the (abundance) of users on dyxum that have the lens they all cry for joy over the bokeh the lens has... i don't doubt it's good, I just don't think it's significantly better than other similar lenses to justify the extra weight/size. That was just my personal experience though, I certainly agree it has a special 'look' to the images it produces, it just didn't suit my 'needs/wants'.

john_cox7 · April 14, 2009

As I understand the 58mm lens scenario, this was the shortest non retro focus lens design of its time. This occurred when most of the rangefinder camera manufacturers were converting their manufacturing processes to SLR cameras and lenses. At that time a lot of the new SLR lens designs were carry overs from the rangefinder era, hence the problem of a quick response to an unforeseen issue of retro focus with short focal length lenses in a SLR mount. Gradually this issue was overcome, with the fast 50mm f1.2 retro focus lenses of the latter film camera era that still exist (along with their predecessors) today.

Most camera/lens manufacturers in those early days produced 55mm lenses of f/3.5 or f/2.8. Some of these lenses were dedicated macro lenses. Others were the basis of future development yet to happen. But for faster lenses, the focal length increased slightly to 57mm or 58mm.

I base my observations from the early days of Nikon when they produced a 55mm f/3.5 Micro (macro) lens and a 58mm f/1.4 lens. From those lenses they developed the 55mm f/2.8 Micro lens and the 55mm f/1.2 lens, which was in turn developed to the 50mm f/1.2 lens. The pinnacle was the 58mm f/1.2 Noct lens. The latter 50mm f/1.2 lens existed up to around circa 2007 and may still exist today as old "new" stock.

Other manufactures as listed above by others have also produced similar lenses over approximately the same period of time.

peterblaise · April 14, 2009

.

Earlier: "... It's no secret that you can put any decent old lens on a camera like the A900, stop it down to f/8-f/11 and get sharp pictures from it... but you're not going to exploit the sensor and most people buying such a camera are in it for the sensor ... "

</blockquote>

Sorry, but the Zeiss paper contradicts your presumption here, where the sensor itself enhances the lens , and their combined MTF curves multiply , so regardless of the lens we use, we ARE getting the benefits of the sensor. Sure, the better the lens, the better the final results, but we are getting the benefits of the sensor nonetheless. Again, thoroughly re-read these and share your interpretations, please!

<ul>

<li>How to read MTF curves Part I: </li>

<li><a rel="nofollow" href="http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_30_MTF_en/$File/CLN_MTF_Kurven_EN.pdf" target="_blank">http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_30_MTF_en/$File/CLN_MTF_Kurven_EN.pdf</a> </li>

</ul>

<ul>

<li>How to see MTF curves in images Part II: </li>

<li><a rel="nofollow" href="http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_31_MTF_en/$File/CLN_MTF_Kurven_2_en.pdf" target="_blank">http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_31_MTF_en/$File/CLN_MTF_Kurven_2_en.pdf</a> </li>

</ul>

</blockquote>

Has anyone used a pinhole on a Sony Alpha DSLR-A900 yet? ;-)

.

ricardovaste · April 14, 2009

Sorry, but the Zeiss paper contradicts your presumption here

</blockquote>

They're not presumptions, you missed the point.

we are getting the benefits of the sensor nonetheless

</blockquote>

Didn't debate that, I said we wouldn't be exploiting it.

exploit the sensor

</blockquote>

You can't put any old lens on the A900 and get sharp across the frame results like you would with a modern ZA lens - that was my point.

the better the lens, the better the final results

</blockquote>

I disagree. If you want ultra high micro contrast, sharp across the entire frame, low distortion results then a more expensive ZA is the clear option for the A900. If you want a high vignette, pastle colours, a softness (ie low frequency), a ZA would not be the option even if would technically exploit the sensor most effectively.

Sign In

Zeiss: on MTF, their 85mm f/1.4 ZAlpha mount lens, the Sony Alpha DSLR-A900 camera, and more

Recommended Posts

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Link to comment

Share on other sites

Create an account or sign in to comment

Create an account

Sign in