Pentax 67 300mm EDIF

[brian_beck1]

I'm considering purchasing the new Pentax 67 300mm f/4 EDIF lens.

Wondering if anyone has used it and can evaluate the optics as

compared to the older 300mm f/4 lens. Thanks!

 

-Brian Beck

[steve_rasmussen]

The real advantage between the older 300mm and the ED is the addition of the tripod mount on the ED. The old 300s were plagued with shutter induced vibration caused by excessive overhang from the tripod. The ED only stops to f/32 while the older Takumar and Pentax go to f/45. As far as optics are concerned, the old five element design did fairly well with color correction considering it used a Cooke Triplet and conventional glass. At the time of its design, it is safe to say that it was corrected for three colors but due to the conventional glass, it will have slight fringing at f/4. This is only detectable under high magnification however. The ED is a nine element design with two low dispersion elements. Unlike the older version, the ED does not appear to be a telephoto design. The rear group does not seem to magnify the image from the front elements, at least it doesn't appear that way from the cross section. This lack of telephoto design is better for performance because the aberrations from the front elements are not magnified. The difference in performance between the two 300s is probably at f/4, but stopped down more than that, there is not going to be much difference. That is, if you don't get any shutter vib on the old 300! A BIG if.

[len_maxwell]

Another major advantage to the new version is

close focusing distance. I think the closest

focus distance for the original 300 was around

13 feet. The new one can focus as close as 8 feet, or

thereabouts. Len.

[rolland_elliott4]

While Steve's answer sounds very academic, it is based on theoretical and not actuall comparison of these two lenses. Which in my opinion is basically useless. Who the heck knows what a Cooke Triplet is? And what makes it better than a Gaussian design, or aprochormatic Tesler quadtuplet? Those were sarcastic questions by the way.

 

The only usefull advice I can give you is to order this lens from Cayman Camera in the Gulf Of Mexico or Hong Kong. CCamera sells it for about $1600.

 

Peace, Rolland

[steve_rasmussen]

Rolland, if you can't stand the technical heat, stay out of the forum!

[jost_von_allmen]

Dear Brian

After two years of successful photography with my 67II with the 55mm and 200mm, strictly outdoors, I have spent the money and just bought the 300mm ED and 2x teleconverter! Before, I have been testing it (rented it from our swiss distributer), shooting several slide films (Fuji Provia F 100 ISO) for testing and comparing with my 200mm and my large format system lenses (240mm APO Ronar, 360mm Nikon ED, 500mm Nikon ED, 720mm Nikon ED), all of which I otherwise usually use with 4"x5". I'm extremely pleased with the performance of the new lens! f4 is o.k., slight vignetting, but sharpness good, even in the corners. From 5.6 to f16 the lens is excellent, f22 and f32 are still good. The old 300mm, without ED, which a friend of mine uses, is definitely a looser now. With the 2x teleconverter, it's more difficult to get good results: shutter vibrations are a problem with this combination, too. Whenever I use the Pentax (on a tripod), I got used to avoid any shutter speeds between 1/60 to 1/4 sec. The 300mm ED doesn't deliver good results in this shutter range neither! It's very well designed for outdoor use, the tripod mount clicks in 90 degrees steps, the lens focuses easily and precisely (I use a grid screen). I really like the internal focusing. It's close up capabilities are very impressive, too. I used it with my extension tubes and got amazing results, meaning that I'm not going to buy the new 100mm Macro for the moment. It's lens hood mounts both ways, with a bayonet mount, so if you reverse it, it's easy to pack away. A well thought out little opening lets you use a polarizer filter without having to remove the hood, it is easily closed with a slide after having turned the filter in the right position.

After all, I'm sure the 300mm is a good investment for serious outdoor work. Especially compared to the difficulties I'm used to when I shoot with 4"x5" in this range.

Jost von Allmen of Switzerland