Here is another field test, but this time it's the 300mm Takumar. This lens and the 300 Pentax are the same optically, as far as I can tell. They are both heavy for their size but very durable as I have discovered by banging the Takumar around. It has survived without any damage. Finish, fit and construction are all quite good with the lens locking in tightly to the camera body with no play. Optics are just average in my opinion. A Cooke Triplet is used in the forward group leading me to think that the lens is Apochromatic (which it may be). The two element rear group is used mostly to flatten the field. This lens is typical of older telephoto designs; it must be stopped down to f/8 to perform. Of course, it is also sharp at f/11, 16, 22 & 32. At f/45 it loses a little due to diffraction. This lens is very sharp at f/22 which is its best focal ratio. Contrast is not as good as the other lenses I'm familar with (45, 75, 105, 200, 600)possibly due to not having SMC on all surfaces. The depth of field scale on the barrel is not as accurate as the lenses just mentioned. For best results, set the depth of field two stops different from the aperature. (Aperature is f/45, depth of field would be set at f/22----Example). This lens likes to be shot at infinity. It seems to perform at its best there. Overall, this is one of my favorite lenses, once you get used to its limitations. Its 3x magnification is very useful for both people and landscapes.

-- Steve Rasmussen (srasmuss@flash.net), February 27, 1998

Answers

Kim: It depends on how large you are going to blowup your pictures. I don't recommend anything larger than 16x20 inch for f/5.6. For f/4, the 16x20 size is pushing it. My test charts with this lens at f/4 proved out my suspicion of unsharpness. SR

-- Steve Rasmussen (srasmuss@flash.net), March 03, 1998.

Anne: Is this really your name or do you like to be anonymous? Yes, the 300mm is a pain but is sharper than most people think. No, it doesn't like tripods, so I've been shooting it handheld with 100 speed film for portrait work. It is sharper than I expected at f/5.6. It could go to 16x20 prints. I am surprised! SR

-- Steve Rasmussen (srasmuss@flash.net), March 29, 1999.

Tapas: An ED, IF 300mm would probably cost around $3600(US)if they made one. The advantage would be closer focusing and better wide open performance. The 300 Takumar/Pentax performs as follows. For 16x12 inch prints, it can do this at any aperture. I can make 20x24 size from f/8 to f/32. At f/5.6, it can make 16x20 prints. At f/4 a 16x20 will be soft. If the 67II has solved the shutter shake problem, tripod use with this lens will be easy. The optics are not the limitation of this lens, but the shutter harmonics from the older body types are.This lens has never color fringed on axis or off axis, indicating excellent color correction. I have used this lens with the Heliciod ext tube and have been mostly successful. If used on a tripod, be aware that any extension will increase the overhang. This really agrivates things when using the old body types. The 67II may not cause enough vibration to affect it. Handheld with Helicoid for portraits can work too although it would be better to use the auto tubes for this. Steve

-- Steve Rasmussen (srasmuss@flash.net), April 01, 1999.

William, thanks for the additional info. When I shoot the 300 on landscapes, I use the slowest film possible and f/45 in order to get the shutter speed out of the danger zones. For handheld portaits, I use Provia F pushed to 200 and 1/125 sec and around f/11 stop. Coma on the new 300 may be improved but I wouldn't bet on it. Usually, when colors are corrected for the marginal zones of a lens, the designer will assume the shooter is going to use the lens wide open more than the older designs. So, there is a better chance that coma at f/4 will also be considered for correction than in the older design. Only a test will show for sure. SR

-- Steve Rasmussen (srasmuss@flash.net), February 01, 2001.

William, this is how I use the 300mm to get tack sharp landscape shots. I use a Bogan 3036 tripod with the legs unextended, a three foot cable release and a Velbon ballhead (PH-173). These are exposures over 1/2 sec and usually around f/22 to f/45. I hold the tripod down with part of my weight and that seems to solve the problems with this lens. The lens does OK with the tripod extended about a foot higher but beyond that it is hopeless. SR

-- Steve Rasmussen (srasmuss@flash.net), February 02, 2001.

It's great to see these field tests - keep them coming. Just one question from someone considering the purchase of one of these beasties. You've said that the lens needs to be stopped down to f8 to perform. How would you rate its sharpness at f5.6 - where I would probably use it quite a bit - and even f4 (for emergencies) ?

-- Kim Fullbrook (kfullbro@cellnet.co.uk), March 02, 1998.

I'd have to say that the SMC Pentax 300mm f/4 is my least favorite of the SMC Pentax lens I own (others = 105f2.4, 165f2.8, and 200f4). The contrast is low, and the sharpness not-so-great even in the f/8-f/16 range. In addition, the lens is an absolute monster. If you shoot this on a tripod, I feel you must have the Kirk bracket (or the equivalent), or forget it. The lever arm is so large that a fly-fart 10 meters away is sufficient to blur the image.

-- Anne Honimous (anne@nospam.com), January 06, 1999.

Hi Steve

I've been following this discussion quite carefully as I still haven't made my decision about which telephoto lens I am going to buy yet. My ideal lens would be an internal focusing (i.e. close focusing) ED 300mm (i.e. a 300mm copy of the 400mm lens). This would be supplemented by a 135 or 165mm lens.

When you say that the 300mm is not as sharp as your other lenses, how does this translate to real application e.g. a 16 x 12 inch photograph of a landscape (stopped down to f8 or smaller) or a portrait (f4 to f8). I have that kind of print (from chromes) from my 105mm and if I could reach that kind of quality (sharpness & detail) I would be more than happy.

Also have you tried the 300mm with ext tubes - how is it ?

The P67II does not have any shutter vibration to speak of - maybe that would alleviate the tripod issue.

Tapas

-- Tapas Maiti (tapasmaiti@hotmail.com), March 31, 1999.

I am contributing belatedly to this thread because I read it before deciding to buy a pre-EDIF Pentax SMC 300 f/4 to use for astrophotography and landscape photography. I concur that best performance of this older lens construction is between f/8 and f/22. Edge performance never gets any better than 70% of center performance in lens resolution tests (lines per mm) at a 19 foot working distance.

The lens has significant coma when used for astrophotography exposures between 10 and 40 minutes. I consider it worthless for this application. I am sure the EDIF version has solved this problem.

I am happier with the 300 f/4 as a landscape photography tool. However, I encountered my first substantial and notorious Pentax 6X7 shutter shake problems with this lens. I have read other threads in this forum and elsewhere on tripod solutions and system weighting solutions to shutter shake image degradation with lenses longer than 300mm and add my observations in hopes of helping others.

Shutter shake vibrations decreased image quality with shutter speeds between 1/15 and 1 second for landscape photography with the 300. I ran lens resolution tests indoors with my Pentax 6X7 and late model SMCP 300mm f/4 lens (pre-EDIF).

Based on information from others, I was able to get reasonably sharp images with the 300 and avoid shutter shake problems with the following setup with 1/2 sec exposure at f/16):

Optimal Setup: Gitzo 1548 (carbon fiber) tripod, Arca-Swiss B1 head, cable release, MLU, and 9 inch Kirk Hugger bean bag sitting on the finder prism.

What happened when I deviated from the optimum setup? In each test, exposure was ½ second at f/16 using MLU, cable release, B1 head, Arca- style non-twisting contour plate. Tests were run on Edmund lens resolution test poster with TMax 400.

1. Remove bean bag from prism: lowered center resolution (lines per mm - lpm) below optimal setup by 29%.

2. Use Bogen 3033 tripod instead of Gitzo 1548: 13% decreased lpm

3. Use Bogen 3221 instead of Gitzo 1548: 37% decreased lpm

4. Use Bogen 3221 and no bean bag instead of Gitzo 1548 with bean bag: 69% decreased lpm

I never had to be this picky with my 165mm f/4 or my 200mm f/4. With the 300, tripod and weighting are critical to decent lens performance at shutter speeds below 1/15 second. I hope this information is of use to others.

-- William Castleman (wcastleman@compuserve.com), February 01, 2001.

Steve: Thank you for your February 01, 2001 comment on potential continuation of EDIF coma and long exposure performance. In my optimum test setup, I tried exposures up to 4 seconds @ f/45. Resolution was poor when I was using a 14 inch cable release. I presumed this was due to cable-associated vibrations when I opened and closed the shutter. I didn’t combine hat trick with these 4 second exposures.

Could you clarify how you are accomplishing your multi-second exposures (e.g., hat trick, long pneumatic release) with the 300 for optimally sharp landscape images?

-- William Castleman (wcastleman@compuserve.com), February 02, 2001.