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Ultra-Wide Angle Optics, 15mm and 16mm


al_kaplan1

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<center>

<img src="http://homepage.mac.com/ramarren/photo/PAW2/large/37c.jpg"><br>

<i>Bride, Isle of Man<br>

©2002 by Godfrey DiGiorgi<br>

Hasselblad 903SWC, Kodak TMax 100, HC-110 1:31 7min@72F<br>

</i></center><br>

The Hasselblad SWC, all models, is one of my favorite cameras. I'd wanted one for many

years and obtained one in 2002. I used it for about a year: It made wonderful

photographs, the field of view is near perfect for my ultrawide needs, and the big negative

combined with that wonderful lens is amazing.

<br><br>

Only reason for selling it was to fund more equipment that I use more frequently/

productively: my work has gone to digital capture in its entirety now. The Pentax DS with

14mm lens returns a similar field of view and not-quite-but-comparable image quality

now.

<br><br>

Godfrey

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The Heliar 15 has a lot of falloff (about 1.5 stops from center to corner) but doesn't

vignette from my experience. Vignetting is caused by some component of the lens falling

within the field of view, causing a shadow. Falloff comes from the fact that the lens' nodal

point is very close to the film plane and the difference between the distance from nodal

point to center vs nodal point to corner is relatively large.

 

Most wide-angle lenses with a short nodal distance show falloff like this and it is

exaggerated as the lens becomes shorter in focal length. The Heliar 15 is an inverted

telephoto design, which helps ameliorate it somewhat, but it's not as strong an inverse

telephoto as a similar focal length lens designed for an SLR, which would pull the nodal

point further from the film plane and generally even the center to corner falloff a good

deal.

 

The Zeiss Hologon 16 shipped with a custom graduated ND filter with 2 stops center

density to counter this fall off issue. Without it, it has almost 2 stops of falloff to the

corners because it is NOT an inverted telephoto design.

 

Godfrey

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Godfrey, your distinction between vignetting and fall-off is an important one. I don't doubt that the Heliar exhibits fall-off, and at its widest aperture, it may even be enough to look like vignetting. My understanding is that vignetting on any lens, if it occurs, is most likely and most pronounced wide-open, and this is probably because the lens is trying to gulp in light rays from the full circumference of the barrel and hence it's more likely that the barrel construction will occlude the corners. At f16, I'm sure there is some fall-off, but vignetting in the form of physical occlusion doesn't seem likely. Here's another shot where I think the tone of the corners is nice and even. At f16, I don't see physical vignetting, nor do I see significant fall-off.<div>00DbHf-25718084.jpg.287d5020c8d5a384ce063f0e9d09b27e.jpg</div>
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Incidentally, and quite O/T, I used a Minolta Spotmeter F to meter off the armoured shield of the Bofors, with the intention that that area come out neutral grey. Shot in color, desaturated to B&W, and it turned out pretty well. The more I try it, the more I think I am just going to standardize on Superia 400 and 100 for both color and black and white.
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Great page. Although I think the distinction between "optical/artificial vignetting" and

"natural vignetting" is a bit of semantics, to some degree.

 

Fred, I can certainly see the Heliar's known 1.5 stops of light falloff in that shot. Happily,

color neg is very tolerant of exposure error and I think it actually helps in this instance.

 

With a 15mm lens, f/16 is well beyond the point where diffraction begins to intrude

seriously on resolution. Since I normally make 11x17 to 13x19 sized prints, I most

normally used my Heliar 15 at f/5.6-f/8 (diffraction begins to intrude between f/6.3 and

f/7.1).

 

Godfrey

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My inside shots are all wide open at f/4.5 and outdoors during the day in the 5.6 to 8 range. Slow shutter speeds are likely to have a bigger effect on sharpness in low light than diffraction will outdoors. As for light fall-off, I usually edge burn my B&W prints anyway but with the 15 sometimes I do the opposite and "edge-dodge".

 

Sometime soon I'm going to try some color with the 15, first time in the 3 or 4 years that I've had the lens! CVS Pharmacy has 24 exp. Fuji 200 on sale for $6.99 in the 5 pack, and I had a CVS coupon for $2.50 off on a $20 purchase so I bought 15 rolls yesterday. To sweeten the deal each box has a $1.00 of coupon for the next Fuji multi-pack purchase. I can't bulk load B&W that cheaply!

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I had the Heliar and yes, it is a fun lens. But for me it was too slow @ f/4.5. I

can't imagine using a lens with a maximum opening of f/8! I sold the Heliar

and used the cash to buy my 50mm Nokton which is now my fastest lens. [My

widest now is the 21mm Elmarit (non-ASPH) which suits me just fine.]

 

If I had the $$ to pay for 120/220 media, pro lab processing fees and a larger

scanner, I agree with Godfrey: the Hassy SWC with its 38mm Biogon is a

jewel of a wide angle camera and in a class by itself!

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<i>.."Slow shutter speeds are likely to have a bigger effect on sharpness in low light than

diffraction will outdoors." Well said!" ..</i>

<br><br>

Did someone say something about using f/16 in low light? In low light, most sensible

photographers will use the Heliar wide open or, at most, stopped down one stop.

<br><br>

Most

sensible photographers will also use a tripod for low light work with an f/4.5 lens, or very

high speed film. Very high speed film will have a greater effect on sharpness than

diffraction as well.

<br><br>

Godfrey

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Fuji's really blowing out their color film at low prices, Al. I hope it isn't the fire sale, but I see the same in London as well.

 

I'm starting to experiment a lot more with using color print film for both color and black and white. The fact that Superia might have a different sensitivity to colors than HP5 or FP4 doesn't bother me too much, at least not yet. "Color print film is more forgiving of exposure error" .... read: "more lattitude" ... read: "Can handle a wider tonal range without blowing out highlights or blacking out shadows". One can do a lot with those characteristics.

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"BTW, I personally refuse to buy the Zeiss 15mm T* in M mount (no matter how good it is) because an M-mount lens in the $4,000 price neighborhood should couple to the RF irregardless of the wide DOF."

 

You realize that the original Zeiss Hologon 15/8 fixed aperture lens also sis not couple to the RF. And it had only a rudimentary focusing scale that skipped from a few meters to infinity. At least the ZM lens has a diaphragm and opens to F/2.8. But it is true, I too would have like to see the lens coupled to the RF.

 

I agree with several other posters that the 15/4.5 Heliar (which I have) is only mediocre in optical quality. It is inexpensive for a lens that wide but it is not in the same league as the Leica ASPH wide angle lenses. You get decent but entirely unspectacular optical quality with this lens.

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I agree... <br><br>

<center>

<img src="http://homepage.mac.com/ramarren/photo/PAW5/large/37O.jpg"><br>

Arundel Castle, UK<br>

<i>©2005 by Godfrey DiGiorgi<br>

Pentax *ist DS + DA14mm f/2.8<br>

ISO 200 @ f/11 @ 1/250 sec, Av mode</i><br>

</center><br>

A 'half-rez' version is available at <br>

  <a href="http://homepage.mac.com/ramarren/photo/PAW5/large/37O-

half.jpg"

target=new>http://homepage.mac.com/ramarren/photo/PAW5/large/37O-half.jpg

</a><br><br>

enjoy,<br>

Godfrey

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