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Pentax M* 4/300 ED F* vs 4.5/300 IF-ED, Nikkor 4.5/300 IF-ED
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PostPosted: Sun Feb 09, 2020 12:37 pm    Post subject: Pentax M* 4/300 ED F* vs 4.5/300 IF-ED, Nikkor 4.5/300 IF-ED Reply with quote

The Pentax M* 4/300mm ED is a small marvel of lens design. It's proably the smallest 4/300mm full frame lens, it has three large ED lenses and one lens made of Schott's equivalent to the Noctilux glass, the LASF31A (nD 1.88, v=40). Some years ago i bought a pristine looking sample - and was quite disappointed about its performance, especially since Marco Cavina in his technical article had been raving about the lens (http://www.marcocavina.com/articoli_fotografici/Pentax_M_300mm_4_star/00_pag.htm). It seems he's never been shooting with it ...!

Last year i got the Nikkor 4.5/300mm IF-ED - another disappointment: Quite strong CAs as well, not better than the Pentax M* 4/300mm, and only slightly better than my Minolta 4.5/300mm IF.

All my vintage 2.8/300mm lenses perform much better, but i still was looking for a small and lightweight high performance 300mm lens.

Some days ago my preferred local camera shop had a Pentax F* 4.5/300mm IF-ED for sale; i took the risk and bought it without checking its performance.

Here are the test results. First image: 100% crops from the center of the 24MP FF Sony A7II. Take these images with a grain of salt, since focusing a tele lens with strong loCAs (Nikkor, Pentax M*) is not straight-forward. I did focus to "best visual sharpness" which results in reddish color cast.

ATTENTION: PLEASE DOWNLOAD THE IMAGES AND WATCH AT 100% RESOLUTION; THE "INTELLIGENT" BROWSER SOFTWARE IS ADAPTING MY IMAGES TO YOUR SCREEN SIZES, RE-SIZING THEM AND BLURRING THEM COMPLETELY ...



And here are the 100% crops from the extreme corner, both wide open (f4.0 or f4.5) and at f8.



It's obvious that the the Pentax F* 4.5/300mm is much better than most "slow" 300mm vintage lenses i know, including a few ED lenses such as the Nikkor 4.5/300 IF-ED and the Pentax M* 4/300mm. The only exception is the Mamyia Sekor C 5.6/300mm which is slower than the lenses shown here, but at least as good as the Pentax F* 4.5/300mm.


Last edited by stevemark on Mon Feb 10, 2020 10:35 am; edited 1 time in total


PostPosted: Sun Feb 09, 2020 12:52 pm    Post subject: Reply with quote

Another good comparison Steve. The pentax 300mm f4.5 has very good reviews on Pentax Forums, and it looks like they are deserved.

Here's a wee qq for you. Did best sharpness and minimum fringing coincide on the Pentax M and nikkor? IME they are usually close (I am thinking mainly of tamron adaptalls I have test pics for) but not necessarily exactly coincident. In which case what should one focus for...?


PostPosted: Mon Feb 10, 2020 10:49 am    Post subject: Re: Pentax M* 4/300 ED F* vs 4.5/300 IF-ED, Nikkor 4.5/300 I Reply with quote

marcusBMG wrote:
Here's a wee qq for you. Did best sharpness and minimum fringing coincide on the Pentax M and nikkor?

No, they don't - and that's what i tried to say before:

stevemark wrote:
Take these images with a grain of salt, since focusing a tele lens with strong loCAs (Nikkor, Pentax M*) is not straight-forward. I did focus to "best visual sharpness" which results in reddish color cast.


This is a problem when testing all non-APO-lenses, but of course it gets worse when you try to compare longer focal lengths. In all my tests, try to focus on "best visual sharpness" (which of course is not an entirely precise definition). Why did i choose this approach? Usually, when focusing on "best visual sharpness", stopping down results in very sharp images without color fringing. However, when focusing on "minimum fringing", stopping down 1-2 EVs results in less detail.

marcusBMG wrote:

IME they are usually close (I am thinking mainly of tamron adaptalls I have test pics for) but not necessarily exactly coincident. In which case what should one focus for...?


Wide open images may look better with less resolution and less fringing (focusing on "minimal fringing"). As soon as you're stopping down 1-2 EV, the images usually look better when focusing on "best visual sharpness". When your are using fast primes, and stopping them down to f8 or f11, the difference is negligible, of course.

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PostPosted: Mon Feb 10, 2020 11:12 am    Post subject: Reply with quote

Oh, i forgot to publish two images of theses lenses on the venerable (and unterrated) Pentax LX:




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