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10-02-2020, 04:15 PM - 1 Like   #16
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I've been thinking since the K-New was more or less revealed that it's time for a new 300/4... we need lenses that can keep up with the body's AF.

Last year I compared my old Tamron Adaptall-2 200-500/5.6 with my equally old A 400/5.6, and noticed about 1/2 stop difference in light gathering with both lenses set to max focal length and f/8. Large zooms are indeed light-suckers.

10-02-2020, 11:24 PM   #17
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My DA* 300mm is my favourite lens by a long chalk (even though I own some stellar lenses). Wonderful rendition. Perfectly good for handheld BIF on the K1 but for one fault - the AF just isn't fast enough.

If Pentax does a new DFA 300mm F3.5 or F4 with 9 out of 10 AF I am totally going to buy one. It would be heaven.
10-03-2020, 02:51 AM   #18
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My guess is that the DA* 300/4 will eventually be replaced by a D-FA* 100-300/4.
10-03-2020, 03:34 AM   #19
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QuoteOriginally posted by tduell Quote
The auto focus on the DFA 150-450 is pretty good. The focus limiter helps a lot. I've used it enough over the years to reckon that it would get focus on most of those potentially great BIF shots that the DA*300 has missed.
The big downside of the DFA 150-450, in my opinion, is how much light it eats. As soon as I started shooting with DA*300 and the 1.4x TC @ f/5.6 (420mm) I soon noticed that it had about a 1 stop advantage over the DFA 150-450, and that really makes a difference when you are chasing IQ with low ISO and high shutter speeds.

Cheers,
Terry
IMO you have to put this into fair perspective. This is what I'm referring to ... the DFA150-450 delivers the following ...

f/4.5 - f/22: 150•160•180•190•200•220•230•250•270
f/5.6 - f/29: 290•310•330•360•380•410•450

In the case of DA*300 you get f/4 open aperture. So at 300 one stop better than the DFA150-450. But go slightly shorter with the DFA150-450 to 270 and you get f/4.5. Not a big difference to the DA*300.

If you put the DA TC1.4x into the equation with the DA*300 you get 420mm @ 5.6 open aperture. The DFA150-450 doesn't need a TC for the FL and you get f/5.6 up to 450mm. So in this case both lenses are comparable concerning "light eating".

If you in further comparison use a 1.4x TC with the DFA150-450 you have to use another one with the DA*300 or instead of a 1.4x TC a 2x TC. Both lenses then show open aperture of f/8.

In both cases the configuration should be usable with autofocus - although very slow for the DA*300 ... think of the coming new long Canon lenses using fixed aperture of f/11 (works since it's mirrorless autofocus tech) !

10-03-2020, 04:57 PM   #20
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QuoteOriginally posted by acoufap Quote
I
If you put the DA TC1.4x into the equation with the DA*300 you get 420mm @ 5.6 open aperture. The DFA150-450 doesn't need a TC for the FL and you get f/5.6 up to 450mm. So in this case both lenses are comparable concerning "light eating".
Maybe I misunderstand what you mean, but in my experience, both lens are not comparable concerning 'light eating'.
My understanding of 'light eating' is that light is lost between lens entry and the sensor.
It all looks pretty much the same in regard to f stop, DA*300 f/5.6 at 420mm, and DFA f/5.6 at 450mm, but that's not a measure of the actual light reaching the sensor.
I'm really talking about the t-stop, and my guess is that the DA*300 + 1.4xTC at f/5.6 is probably not too far from 5.6, whereas the DFA at f/5.6 is probably up around 8....ie somewhere around 1 stop advantage to the DA*300.
I haven't done any controlled tests, they are probably best done indoors with controlled lighting, but real world shooting with the DA*300 does seem to allow lower ISO/higher shutter speeds.

Cheers,
Terry
10-04-2020, 12:22 AM   #21
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QuoteOriginally posted by tduell Quote
Maybe I misunderstand what you mean, but in my experience, both lens are not comparable concerning 'light eating'.
My understanding of 'light eating' is that light is lost between lens entry and the sensor.
It all looks pretty much the same in regard to f stop, DA*300 f/5.6 at 420mm, and DFA f/5.6 at 450mm, but that's not a measure of the actual light reaching the sensor.
I'm really talking about the t-stop, and my guess is that the DA*300 + 1.4xTC at f/5.6 is probably not too far from 5.6, whereas the DFA at f/5.6 is probably up around 8....ie somewhere around 1 stop advantage to the DA*300.
I haven't done any controlled tests, they are probably best done indoors with controlled lighting, but real world shooting with the DA*300 does seem to allow lower ISO/higher shutter speeds.

Cheers,
Terry
Thanks! - Never had a deeper look at this t-stop thing. Now read (wikipedia) here about it and think I now understand what it's about.

I'd test it but don't own the DA*300.
10-04-2020, 10:49 AM   #22
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QuoteOriginally posted by tduell Quote
What I would like is for this lens to be updated, using the existing optics, but incorporating a modern fast focus motor, and a focus limiter with (say) 5-inf, 2-5, and full options.
I reckon such an updated lens would be a great addition to the Pentax line-up for sport and wildlife shooters.
Yes it would.
Which Star Lens you want a renew and HD version mostly now? - PentaxForums.com

I'd love an 400mm f4.5 like the Minolta:
Minolta AF 400mm F4.5 HS APO G A-mount lens info
10-04-2020, 02:42 PM   #23
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I agree- the DA* 200mm f/2.8 and 300mm f/4 lenses have antiquated AF systems.

I don't have the DA* 300mm, but I do have the DA* 200mm f/2.8 which is of the same SDM vintage and AF is certainly not the fastest. My DA 18-135mm DC is easily better! An upgrade to a good DC motor for these telephoto prime lenses would be a welcome change. And compatible with most all Pentax camera bodies. I do have the older FA* 300mm f/4.5 which has screw-driven AF and is quite fast and accurate especially on my KP body.

10-05-2020, 01:07 AM   #24
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I would be super-interested too for an upgraded DA*300mm with better/faster/more precise AF... I hope it sit somewhere on an unpublished roadmap...
10-05-2020, 03:35 AM   #25
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I find the 150-450 is so sharp I could cut myself on it almost as wide as the aperture will go. My problems with it are twofold: it's bulky and heavy and hard to move around quickly, even on a gimbal mount; secondly, there's no way to lock the zooming part, which, if I have it extended towards the greater telephoto range, it tends to slide back in if it's pointed upwards (e.g., attempting to track birds in flight).

The 560 is an APS-C lens, and there's no getting around that by my lights - too much vignetting at wider apertures with a K-1, and since it starts at f/5.6 it's not so flexible in less than perfect light. Works great with a KP, though.

I do have an FA* 300mm, which I much prefer for that purpose. That's the one that was discontinued in 1991. Got it used, and I love it.

Got a 2x TC with it, as well, but almost never use it on that lens - more useful for moon pictures & extreme landscapes with the 560mmm.

Seems to me that there's so much more variation among lenses of the same model, it's almost impossible to make sensible comparisons. I suspect OP's 150-450 isn't as sharp as it ought to be, and that I got "the good one" that came off the assembly line that day. I assume the calibration has been done as well as might be, so perhaps that one needs to go to the lens-hospital.
10-05-2020, 04:22 AM   #26
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QuoteOriginally posted by dlh Quote
  1. The 560 is an APS-C lens, and there's no getting around that by my lights - too much vignetting at wider apertures with a K-1, and since it starts at f/5.6 it's not so flexible in less than perfect light. Works great with a KP, though.
  2. I do have an FA* 300mm, which I much prefer for that purpose. That's the one that was discontinued in 1991. Got it used, and I love it.
  1. No, the DA 560mm is an FF lens with a low vignetting. Vignetting is as low as Canons 600mm f4 or other ultratele lenses.
    I always shoot it wide open.
  2. The F* 300mm f4.5 was discontinued in 1991. The FA* 300mm f4.5 was introduced in 1991.
    Template:Pentax K-mount AF lenses timeline - Wikipedia
10-05-2020, 09:53 AM   #27
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QuoteOriginally posted by angerdan Quote
  1. No, the DA 560mm is an FF lens with a low vignetting. Vignetting is as low as Canons 600mm f4 or other ultratele lenses.
    I always shoot it wide open.
  2. The F* 300mm f4.5 was discontinued in 1991. The FA* 300mm f4.5 was introduced in 1991.
    Template:Pentax K-mount AF lenses timeline - Wikipedia
No, the DA 560 is an APS-C lens, that's what the "DA" part means.
HD Pentax-DA 560mm F5.6 ED AW Reviews - DA Prime Lenses - Pentax Lens Reviews & Lens Database
You can live with the vignetting on a fullframe camera, but I don't like it. Each to his own.
QuoteQuote:
The smc PENTAX-DA, HD PENTAX-DA, smc PENTAX-DA L, and smc PENTAX-DA* lenses are designed to be used exclusively on digital cameras with an APS C sized sensor (the K and *ist D digital camera series). Their image circle covers only the 18 x 24mm format of APS C sized sensors so the corners of the image will come out dark if the lens is used on a 24 x 36mm film camera or a 24 x 36mm full-frame digital SLR.
...
Pentax K-Mount Lenses Explained: The differences between various Pentax lens series

You're right about the 300, mine's the one that was discontinued in 2004.
10-05-2020, 10:02 AM   #28
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Pentax says this about the DA 560mm:
Attached Images
 
10-05-2020, 01:08 PM   #29
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QuoteOriginally posted by Pål Jensen Quote
My guess is that the DA* 300/4 will eventually be replaced by a D-FA* 100-300/4.
This is perfect. I can't think of another lens I'd want more at this time

---------- Post added 10-05-20 at 04:16 PM ----------

QuoteOriginally posted by Billk Quote
My DA* 300mm is my favourite lens by a long chalk (even though I own some stellar lenses). Wonderful rendition. Perfectly good for handheld BIF on the K1 but for one fault - the AF just isn't fast enough.

If Pentax does a new DFA 300mm F3.5 or F4 with 9 out of 10 AF I am totally going to buy one. It would be heaven.
I could have made this same post.... FA 77, FA 31, D-FA 50 1.4, D-FA 150-450, DA* 55..... NONE come close to the images I made from the DA* 300. I rarely if ever used AF on it though. I sold that lens to someone on here.... hopefully it has served him well!
10-05-2020, 03:29 PM - 1 Like   #30
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QuoteOriginally posted by dlh Quote
Seems to me that there's so much more variation among lenses of the same model, it's almost impossible to make sensible comparisons. I suspect OP's 150-450 isn't as sharp as it ought to be, and that I got "the good one" that came off the assembly line that day. I assume the calibration has been done as well as might be, so perhaps that one needs to go to the lens-hospital.
I agree that there is variation among lenses, but I have confidence that my DFA 150-450 does provide good results. The lens was recently calibrated by the local distributor and service provider (our local lens-hospital), and to my eye it produces excellent results, but I reckon my DA*300 does that little bit better. I don't think there's much in it.

Cheers,
Terry
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