Hasselblad 500C/M - Fresnel Screen & Acute Matte D ??

Hello everybody,

 

I have just joined the site after consistently coming across practically the answer to most of the questions

I have raised on google.

 

I have just purchased a Hasselblad 500C/M after wanting one for many years and it comes with numerous

extras, alot of which I am familiar with.

 

I was wondering however from a relatively new person in the MF field and only really using a SLR from an amateur point of view on auto, what is a Fresnel screen and Acute Matte D? Additionally what do they do

and what are the benefits?

 

Many thanks in advance.

 

Kind regards,

 

Mark.

The Acute Matte D is the brightest, latest screen available from Hasselblad. I have one on my

500CM and it is a whole lot better than the screen that it had originally. FOr me it is much

easier to focus.

Bob,

 

Thanks for the prompt response, am I correct in saying then from your response that the

fresnel screen is the original and the acute matte D is an upgrade? What is the purpose of

this, does it give a clearer brighter photo i.e. better definition and contrast or is it a visual

aid when setting up the photo? It may become clear once I receive the item but I was

wondering in advance.

No, there is a fresnel screen incorporated into the Acute Mattes. A fresnel makes evens out

the light so the corners of the screen are relatively equal in brightness. The screen is a focus

aid, no more, no less. An original screen is ok bright, a Hassy bright matte is a little brighter,

an Acute Matte even brighter, and an Acute Matte D is the brightest.

Hi Bob,

 

Thanks for your response, I feel alot clearer now on the purpose of the screen. Many thanks

for your time, it was much appreciated.

A Fresnel screen (q.v. on Wikipedia) is a "collapsed" lens that directs light at the edges of the screen toward your eye in the center, making the image much brighter than a plain ground glass.

 

Acute-Matte screens go a step further. Instead of a randomly ground finish, the screen is composed of microscopic prisms that act much in the way as a Fresnel lens, but with a nearly invisible pattern. This screen is sandwiched with a true Fresnel lens with very fine rings.

The Acute Matte D, to my knowledge, is the basic Acute Matte screen with the addition of a split-image focussing aid and a grid. The grid is very helpful for correct image geometry, icluding architectural subjects and precise copy work. I am not aware that it is any brighter as Bob suggests.

 

http://www.amazon.com/Hasselblad-Focusing-Acute-Matte-Architectural-42217/dp/B0000BZLKU

The following quote below from someone who said he was a a Hasselblad optical department employee may be helpful here:

 

 

Per Nordlund , sep 28, 2001; 01:53 a.m.

A short Hasselblad contribution to this thread:

 

1)Acute Matte D screens were not designed to be brighter, but to have better focusing properties. If you look at out-of-focus highlights with an old Acute Matte and compare with a new D type the difference is quite visible. The new ones "snap" in and out of focus in another way.

 

2) Visual characteristics of different focusing screens aside, there is one thing buyers of our metering viewfinders should perhaps consider: When designing a lightmetering system, a great deal of work is put into optimizing the sensor placement, so that it will work together with the diffusive characteristics of the focusing screen in an optimal way.

 

** Go to the original page as well if you want to see a photo of a D screen:

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00JXEK

Oh, and there are Acute Matte D screens that do not have the split image or grid lines.

 

B&H photo actually shows 7 differing models here:

http://www.bhphotovideo.com/bnh/controller/home?shs=acute+matte+D&ci=0&sb=ps&pn=1&sq=desc&InitialSearch=yes&O=RootPage.jsp&A=search&Q=*&bhs=t

 

You don't find any on the Hasselblad USA site. Honestly, I have a hunch that they're either going to cease making the screens before too long or they've already ceased and only selling whatever stock is remaining.

 

Please, however, take that with a very big grain of salt as it is only speculation and opinion on my part. Since they've nearly quit making everything else though...it seems to be at least reasonable....reasoning.

Yes Ken, after posting my comments above, I did some searching around. First point, it is easy to be confused by the changes in nomenclature of the various screens, as I clearly have been. And regarding the Hasselblad Websites, it has been the same all around. My first stop was usually Hasselblad.se, but I don't bother much any more, because they are simply not the same helpful company we used to know, especially if one is interested in and using 6x6 film. None of the announcements from "Hasselblad" addressed to their "valued customers" include us. Meaning to say, that unless one is using the so-called "H system" (Fujiblad) you are no longer included as one of the "valued".

Yeh I'm with ya Kevin. Seems perfectly obvious that they are trying to distance themselves from the V crowd. So it goes. They'll either make it or they wont. The market will dictate that in due time. It always does. I don't wish anything bad on 'em but it's a hard pill to swallow for sure.

Re the difference between Acute Matte and Acute Matte D:<br><br>The thing with Acute Matte screens is, as Edward wrote, that they use an optical device (actually very, very many) to direct light towards a single point, where your eye is supposed to be.<br>This makes the image a lot brighter than the one a regular diffusing screen presents (they scatter light in all directions; a lot of it will not reach your eye).<br>But whereas a diffusing screen presents a rather well defined plane in which the image is located, the optical devices on the Acute Matte create an aerial image, with considerable depth.<br>The result is that your eyes can see the image sharp, not just when it is in the single plane where it is supposed to be seen sharp, but also when it is a bit outside that plane. You can turn the focussing ring a bit, and still see the image sharp.<br><br>So Acute Mattes are very bright. But using the word "snap" to describe how the image appears in focus is far from accurate. Though the old diffusing screens also present an image with a certain depth (the height of the diffusing structure), they are the ones that let you see the image "snap" into focus.<br>So what they did to improve the Acute Matte is already given away by the "D" in the name: they made the screen - while retaining the microdevices - a bit more like a "d"iffusing screen by roughening the surface of the devices.<br><br>But still the old screens "snap" in focus in a much 'snappier' way than even the Acute Matte D.<br>But it's a trade off: dim, but 'snappier', or bright and fuzzy.<br><br>Acute Matte screens of both types also have another peculiarity: due to their micro optical devices, the out of focus parts of the image do not look like how they will appear on film. It's hard to judge them, and thus the visual balance between in and out of focus parts (a compositional tool) using Acute Matte screens.

There's also a distinct difference in metering ( TTL )between the Acute Matte and Acute Matte D. If using the PME45, it's recommended that exposure should be increased by 1/3 to 2/3 EV for lenses with max.aperture 5.6 or larger, and, conversely, reduced by the same ratio for lens of max.aperture of f/8 or smaller if using the Acute Matte ( matrix metering )while the Acute Matte D requires no adjustments.

 

I've been trying out the PM45 (VFC-6) recently and found that in using the Acute Matte D the ASA rating ( using 100 ASA film )has to be set at 50, while using the Acute Matte the rating set to 25.

Thanks everyone for all the information and the links which helped enormously. I know

understand the purpose of this piece of kit.

You're welcome Mark. I picked up some new info myself.