per_nordlund

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.

I work with lenses and lens testing at Hasselbald, so I've cleaned some lenses over the years. It's actually quite difficult to do well, so I have to agree with Roger: don't clean lenses unless you have to. (Which does not mean that you could leave your lenses dirty; that does of course reduce image contrast.)

I don't know why Hoya recommend not to use lens cleaning fluid. It seems strange that it would be possible to damage coatings chemically without extraordinary stuff, but I can't say they are wrong. I do know, however, that some filter brands are really difficult to clean. For example it can be easy to get "drying marks".

So, blow off the dirt, and clean with a good cloth or tissue. (Some tissues are not soft enough. Kleenex is quite OK(!).)

Be CAREFUL not to get dirt or grease from the front (or rear) cover ring (or from below the ring) onto the lens surface.

My favourite fluid is homebrewed: A mix of ether (20%) and ethanol (hope that's the correct name). We use "spectrographically clean" ethanol at 99.5%(!). This mix dries at a nice pace and takes care of most problems, with one big exception: fingerprints. For that you have to get something like acetone into the mix. And then you really have to be careful when you get close to the plastic front cover ring!

An answer from Hasselblad: It sounds like you have bought one of the "C" lenses that were produced for the "Classic" camera. (This was some time before the introduction of the CB series.)

Anyway, your lens is basically identical to a CF 80 lens. The only differences I can remember are:

1) Only white graphics on the lens

2) No f-position on the shutter speed ring

 

If I'm correct your lens has the 60 filter bayonet.

 

Best regards

Some extra input from Hasselblad: If you want to find data on entrance and exit pupil diameters for Hasselblad lenses to put into Mel's formulas, please visit the Zeiss site, www.zeiss.de.

Being a Hasselblad optical department employee, I have to say that some of these threads do provide terrific reading. Daniel, thanks for your confidence.

 

Per Nordlund

A comment from Hasselblad: It sounds like you are mixing up the 5.6/30 Aspherical lens for the XPan camera with the "regular" CFi 3.5/35 lens.

 

Per Nordlund

Guess I'm one of the horses mentioned above, since I made a submission to a thread about CF and CFi lenses. This was my first ever contribution to MFD, and I sure had a hard time before deciding to post it. Since most (but not all) readers seem to value this type of response it might be OK with an odd "manufacturer-reply" like mine every now and then; as long as they stick to facts.

 

Per Nordlund

Since I work with optical design at Hasselblad I might be able to give some information on this issue:

 

Dieter, none of the statements are wrong. The CFi lenses have higher image contrast due to reduced straylight levels. This has nothing (or very little) to do with MTF graphs. The term "contrast" when used in an MTF context refers to the modulation transfer ratio. It is a bit unfortunate that the same word is used with two different meanings, but this seems to be the common language use.

 

Robin, a) yes, the CFi lenses have lots of ergonomic refinements to improve handling and b) no, they are not cheaper to manufacture.

 

Even if the optical designs for the CFi lenses are identical to those for the CF lenses the optomechanical improvements (things like the properties of the black paint used on the lens diameters, the shape and surface characteristics of lens fittings and baffles and so on) introduced with the CFi program will under certain conditions result in significantly improved image quality. (One excellent example of "certain conditions" is fashion or product photography with a white background.)

 

Marketing ploys or hype..... I would like to call all this "product development". Better lenses at just about the same price sounds fine to me.

(I've worked for sooooo many hours with these things; I just couldn't hold my breath.)

 

Per Nordlund