thilo_schmid

Thanks again for answering.

<p>

The benefit of asymetric tilt and swing is that both axis go exactly

through the film plane. Thus a subject in the center of the ground

glass will not loose focus when applying tilt and swing (in any

combination). Studio monorail view cameras equipped with such

features usually allow you to take the degree readings from a scale

and transfer them to the front standard (in opposite direction, of

course), since rear tilt or swing will change perspective. This is

exactly why I asked for degree scales on the ebony.

<p>

BTW: The Arca Swiss Orbix Option will allow kind of asymetric tilt

and swing with the front standard. The swing axis will in this case

not move while tilting - it always goes through the center of the

lens.

GreyWolf,

<p>

thank you very much for this review. It was a pleasure to read.

<p>

May I ask three more questions to the Ebony Experts?

- how long does it take to set up a folding Ebony?

- what is the difference between the SV45U and the current SV45U2?

- Is there a degree scale to transfer rear tilt and swing to the

front standard?

<p>

Thanks again

Ross,

<p>

Mine starts at f6.8, too. You should not worry too much about it. You

neither will take pictures wide open nor will you need to set it to

f6.8 for focussing. Just make it fully open to get f6.8. Your lens

has probably been remount in another shutter some time. As long as

your get properly exposed Pictures at f22, you may ignore this. Just

make a test picture.

Mark,

<p>

you may get Newton-Rings when placing a sheet-filter directly onto

the negative. I don't know the Omega D-2, but doesn't it have a

seperate filter drawer?

Phil,

<p>

there have been three different color heads for the L138. CLS 300,

CLS 301 and CLS 1000. The former ones had an external fan unit. You

must connect the hoses in the right order. Check whether your fan

unit is equipped with a dust filter (should be). You may need a new

filter. Make a test run without filter. It sould not get that hot

within 30 Seconds.

Phil,

<p>

leave it as it is. Your CLS 300 is bright enough to deal with a dust

on the filters. As you may have noticed, the screws are sealed,

because the alignment of the filters has been calibrated to the scale

on the dials. Removing the filters for cleaning will require a

complete disassembly and a new calibration.

<p>

Regards,

Aaron,

<p>

you can find a brief description of one possibility under

http://www.luminous-landscape.com/panorami.htm

However, Radial Gradients in Photoshop will not allow an exact

simulation of the cos4-falloff

Pete, in the first part of my explanation, I was talking about an

ideal lens. The amount of information availiable to the film is

independent of the image circle. But the resolution, measured in dots

per in inch, is not. Otherwise you would be able to increase the

amount of information availiable to the film by just increasing the

image circle, regardless of the diameter of the diaphragm. This ist

physically not possible. Diffraction Limits mean "Information Limits".

<p>

The more suqare format sized LF will not save you more information

als long as a larger image circle is desireable. The amount of

information captured by film depends on the percetage of the image

circle actually used, not on its aspect ratio. In LF, a much larger

image circle is usually desired. This is why Coverage is more

interesting than Resolution. The cost for that is loss of

information. But LF will compensate for this. And it will do so

forever, because even if manufacturers will push film resolution far

beyond todays limits, the sharpness and color saturation of their

enlargements will be diffraction limited by physics, too. Diffraction

happens on every pixel.

<p>

BTW: the most potent 35mm photographic lenses are those built for

microdocumentation systems with 35mm non-perforated film, like the

Zeiss S-Planar 5,6/60 and Zeiss S-Biogon 5,6/40. There resolution is

at least 250lp/mm in the outer image circle and near 350lp/mm in the

center. They are "the perfect lens" for 35mm-enlargers, if you can

get one...

Even the resolution of an ideal lens is diffraction limited according

to the laws of physics. The limitation is imposed by the opening of

the diaphragm. For obvious reasons, the resolution behind the lens

cannot exceed the resolution of this "point". Since this opening is

usually smaller than the film format size, the image must be

expanded. Expanding the image will lower the overall resolution,

since there is no way to "add information" behind the diaphragm.

<p>

If you compare two *ideal* lenses of the same speed for different

film format sizes, they will yield exactly the same amount

of "information". The only difference is their "density".

<p>

In an ideal system, the question is not film size but film format.

The square format will capture most of the resolution provided in the

image *circle*

<p>

So LF has actually less usable resolution, because the image circle

is and needs to be larger than film format. On the other hand, film

and lenses are still far from beeing ideal. Since film does have a

limited resolution on its own, the combination of lens and film is an

optical system, too. The combined resolution of this optical system

is always less than the resolution of the weakest element. In LF,

film is not the limiting factor, because film resolution is always

higher than lens resolution. As long as film resolution is not

improved far beyond todays limits, LF will always capture more

information than MF or even smaller formats.

The Ronar is originally a process lens and is corrected for flat

field, too. It is not specially optimized for close up beyond 1:1.

But it is suitable for macro work, because of the smaller image

circle. The smaller the image circle the less resolution you will

loose with macro work. A normal (telephoto) lens will have a huge

image circle at macro bellows extensions. So you will be using only a

small fraction of the optical performance of the lens. The Ronar is

the more general lens and has also a good performance at infinity.

Since you already have a Schneider 150mm, I would not recommend the

APO Ronar 150mm. Either take the Macro Sironar or a Scheider Macro

Symmar. On the other hand, an Apo Ronar 300mm would be a good and

cheaper choice, because you can use it for many things, e.g.

portraits and even landscapes. But you will need an extenstion rail

to do macro work.

If you want to get real close, e.g. beyond 5:1, you should consider

buying a loupe lens like the Zeiss Luminar. They are out of

production, but you can find them on the second hand market or on

Ebay from time to time.

Trevor,

my original equipment center filter for the Apo-Grandagon 4,5/55

says "ND 0.45" which equals 1.5 f-stops or an exposure factor of 2.8x