Pentax K 300mm f4 no better than the DA 55-300mm?

*DanielT74* · 06-16-2009, 07:12 AM

This could of course be due to my (lack of) skill, but I recently got a mint K 300mm f4 and tried shooting the moon with it. For starters the pentax 1.7x TC didn't improve the image quality much at all and with or without the TC, the shots were comparable to the zoom. I was surprised. Will the pros shed some light on this? Or should I just start saving for the F*, FA* or DA* 300mm?

Shots here http://www.pentaxforums.com/forums/633647-post30.html

Note the first shot was taken on the night before the others (sorry).

*Ash* · 06-16-2009, 07:26 AM

G'day mate.
I'm no pro, but I can say that the TC won't improve IQ, rather it degrades it (even if ever so slightly with such a great TC such as yours). Shooting the moon aint as easy as it seems. Longer focal lengths would be more helpful, but I wouldn't get a 'better' one just to be able to shoot the moon...

vizjerei · 06-16-2009, 07:47 AM

What's the aperture did you use? I usually use at least f8 or smaller, enough depth of field is important for taking pic of the moon.

and yes, TC won't improve IQ, it only increase the reach of the lens, using better TC only give you less "degradion"

Mike.P® · 06-16-2009, 08:29 AM

I have had the K 300mm f4 and the 55-300mm (before buying the F* 300mm f4.5) and can honestly say I think the 55-300mm is actually better. Now the F* 300mm f4.5 and 1.7x TC is another thing entirely ... very nice and very sharp.

**Marc Sabatella** · 06-16-2009, 11:08 AM

Not sure how much moon photography you've done, but the moon is a tough subject in lots of ways - hard to nail focus since there is nothing in front or behind it to help gauge things, and being so far away is subject to all sorts of atmospheric effects. Plus of course it moves - way faster than most people realize. not sure what aperture or ISO you used, but at 300mm, you need a pretty fast shutter speed to freeze that motion.

Anyhow, all of that is to say, the lens might not be the primary determiner of IQ here. If you're trying to test the lenses, you're better off with an easier to control subject.

But FWIW, I guess it wouldn't surprise me if the K300/4 wasn't all that much better than the DA55-300. After all, the M200/4 isn't appreciably better than the DA50-200, either, aside from being a stop faster and easier to focus manually.

*8540tomg* · 06-16-2009, 02:32 PM

Daniel,

I haven’t used the DA 55-300 but I have a lot of experience with the K 300/4. I wouldn’t give up on the old lens yet. The lens is capable of delivering stellar images but it takes some getting used to. It is fully manual of course and this in itself is a major learning curve if you don’t have much experience with MF lenses. The green button helps but it is far from perfect where exposures are concerned. The lens is also quite heavy and requires a solid tripod for best results.

Pentax Lens Review Database - 300mm F4

The lack of a tripod collar is discussed at length in the above forum reviews on this lens.

I had one made for mine and it made a dramatic improvement in performance. The other thing that helped greatly was the experience gained by using the lens exclusively for about a month. This lens, like many from its generation, is prone to PF and chromatic aberrations but you can work around some of these issues.

Marc is correct in suggesting you might want to start with and easier subject than the moon as you develop your skills with the old 300. I’m just speculating but I suspect you will find, with practice and effort, the K 300 outperforms the DA at the 300mm setting. Work with it for a month or so and then make another comparison. I think you will be pleased.

Here's a couple from the K 300 last year:

Cheers

Tom G

*Ash* · 06-16-2009, 07:58 PM

Great examples of what this old prime can do, Tom.
It's got that 'film' like rendition too.

jocko_nc · 06-16-2009, 10:46 PM

WOW. Those shots are sick good.

jslifoaw · 06-16-2009, 11:21 PM

I have the K300/4 and the T6-2x. The lack of a tripod collar makes it extremely vulnerable to shake, and SR can only do so much. It is also a bit soft wide open. However, when used properly, it can offer very good results.

The shot below was taken on a windy night at 600mm, proably around F13-16, tripod mounted (but no collar remember), plus the tripod was crappy and weighed less than the camera+lens. So basically a terrible setup, but it turned out ok with a bit of motion blur.

Flickr Photo Download: IMGP2673

Dr_who · 06-17-2009, 02:09 AM

I'd have to agree judging a lens on moon taking wouldn't be a good test. the camera IQ seeing a big white circle in the middle of darkness. I think you should fool around with settings. Try maybe under exposure very slightly and brighten it up in post work. Using a slow shutter on a object as bright as the moon traveling at 3,680 kilometers per hour causes problems.

If you want to test the image do focus tests, colour tests, DOF tests would be a good idea. Something still life would be good as well with a tripod stationary and use the same settings/lighting and time of day to get the most accurate results.

asdf · 06-17-2009, 02:19 AM

Originally Posted by Dr_who

Using a slow shutter on a object as bright as the moon traveling at 3,680 kilometers per hour causes problems.

It won't cause a lot of problems because it's far away and is very bright:
Parallax - Wikipedia, the free encyclopedia

Shooting stars or dimmer objects is a different matter...

Ben_Edict · 06-17-2009, 02:41 AM

Originally Posted by asdf

It won't cause a lot of problems because it's far away and is very bright:
Parallax - Wikipedia, the free encyclopedia

Shooting stars or dimmer objects is a different matter...

You should not forget the magnification of a tele lens. The moons travels roughly 15 degs per hour, which is a movement of about 15 arcsecs per time second or in other words: The moon travels so fast on its orbit, that you can discern its movement within 4 seconds with your naked eye! So any exposure time above 1/2s with a 300mm lens will show visible motion blurr. This time goes down when adding a tc.

Ben

Ben_Edict · 06-17-2009, 02:43 AM

Originally Posted by DanielT74

This could of course be due to my (lack of) skill, but I recently got a mint K 300mm f4 and tried shooting the moon with it. For starters the pentax 1.7x TC didn't improve the image quality much at all and with or without the TC, the shots were comparable to the zoom. I was surprised. Will the pros shed some light on this? Or should I just start saving for the F*, FA* or DA* 300mm?

Shots here http://www.pentaxforums.com/forums/633647-post30.html

Note the first shot was taken on the night before the others (sorry).

Your images do not show any meaningful difference or advantage of one lens over the other. First the images are small (but that could still be a 100% crop at such a short focal length...) and secondly they are processed and thirdly they lack EXIF info, so it is hard to say, which factors may have influenced the results (exposure time, aperture) and lastly we have no idea about your set-up (is the tripod up to the task?)

If you could post the missing data, we might be able to give a clearer response.

Ben

asdf · 06-17-2009, 03:34 AM

Originally Posted by Ben_Edict

You should not forget the magnification of a tele lens. The moons travels roughly 15 degs per hour, which is a movement of about 15 arcsecs per time second or in other words: The moon travels so fast on its orbit, that you can discern its movement within 4 seconds with your naked eye! So any exposure time above 1/2s with a 300mm lens will show visible motion blurr. This time goes down when adding a tc.

Ben

OK, but the moon is very bright. I'm ashamed to say this, but I too have shot the moon.

(1000mm, 1/160 s, f/11, ISO400 exposure)

07d 06h photo - Neil Rothschild photos at pbase.com (not mine)

Ben_Edict · 06-17-2009, 05:10 AM

Originally Posted by asdf

OK, but the moon is very bright. I'm ashamed to say this, but I too have shot the moon.

(1000mm, 1/160 s, f/11, ISO400 exposure)

07d 06h photo - Neil Rothschild photos at pbase.com (not mine)

You're ofcourse right, the moon is bright at Full Moon - but its brightness diminishes massively with the moon's phase, which is the main problem, when photographing the moon.

I guess, you have made similar experiences as we all did, when trying to photograph the moon: despite this brightness level, it is very hard to obtain a sharp image. Apart from the inherent properties of the lens or telescope used, there are so many variables, which are beyond control (atmospheric seeing, being very important) or need to be controlled tightly (camera shake for instance), that a really tack sharp image is a rare result.

And as there are so many factors to consider, it is a very unsuitable subject to compare lens performance!

Ben