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05-02-2008, 03:35 PM   #1
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DA*300 Sample 100% Crops (Some with Kenko 1.5x and 2x TCs)

I was asked to provide some 100% crops of some images taken with the DA*300. I set up the boxes shown below on a table in our garden for the purpose of the experiment. I am not used to doing this kind of thing so please feel free to comment on the procedure as well as anything else. I wanted to take images using the lens on its own as well as with the Kenko Teleplus 1.5x DG TC and Kenko Teleplus 2x MC7 DG TC. In practice I have concentrated on the upper TC box on the left for the crops. I took shots at every aperture with and without the TCs. I have only included the ones with the lens at F4 and F8 here. If you want me to post any others please let me know. As with most lenses I think IQ improves with the lens stopped down a bit. For the shots with the TCs I moved the table further away as it seemed a good idea to have the image roughly fill the same area of the frame. The camera was on a tripod and I used a cable release to fire the shutter. I realised after doing all this though just how much a camera can shake even using this method. I was surprised how much the camera juddered each time the shutter fired. In hindsight I have realised the carpeted surface that it was on was not ideal. It would have been better on a more solid surface. Also perhaps I should have further dampened any movement by placing my hand on the lens? The other thing I should mention is that all these were taken at 800 ISO. I meant to adjust to a lower ISO setting but forgot. Also camera settings were at Sharpness +2 and Contrast +1. I have had the camera permanently on these settings following advice in a Review when I first bought it. Anyhow, hopefully all these factors are not that significant.

Just to clarify that the Kenko Teleplus 1.5x is the SHQ version with the power zoom contacts. The 2x has similar contacts. The boxes that Kenko supply for their TCs are confusing as they do not give precise information as to the model.

Overview:1/2000th, F8


When I was first asked to do 100% crops I wasn't sure what this meant. I think I have found out the meaning but I had better explain the procedure that I followed just in case I've got it wrong. I used Corel Paint Shop Pro Photo XI to view each image at 100% and then did a crop of the image. If this isn't the right procedure please let me know.

Lens on its own, 1/4000th, F4


Lens on its own, 1/2000th, F8


Lens with 1.5x TC, 1/2000th, Lens at F4


Lens with 1.5x TC, 1/750th, Lens at F8


Lens with 2x TC, 1/1000th, Lens at F4


Lens with 2x TC, 1/350th, Lens at F8



For those of you who prefer a live subject this is a 100% crop of the squirrel image I posted a few days back. This one was hand held.

Lens on its own, 1/180th, F8, Exp Comp -1.0


Paul


Last edited by channeler; 09-25-2011 at 05:41 AM. Reason: Clarify Versions of Kenko Teleplus TCs
05-02-2008, 04:17 PM   #2
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Thanks for posting your shots!

For some reason the "Lens with 1.5x TC, 1/750th, Lens at F8" sticks out at me. Maybe it's the clarity of the "for PENTAX" text at the bottom of the image.

Overally, have you seen much IQ degradation with the TC's?
05-02-2008, 05:06 PM   #3
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Very good, thanks for this. The lens seems very clear indeed. I also noted the clarity of the 1.5x f8 shot as Gregory mentioned. It seems its perhaps just slightly more magnified (box was perhaps a little less than 50% farther back).

Shots bode well for the 1.5 and the lens in general, I'd certainly not hesitate to buy based on your test, except I don't use the focal range enough to justify it personally.

Kelly.
05-02-2008, 06:56 PM   #4
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Channeler,

Good test.

Does the lens have a tripod mount? I have a very very older (perhaps the 1st version) of Pentax 300/4..It doesnt have a tripod mount n I'm thinking of ways in which it can be mounted on tripod without risking my k10d as well as the lens..

thanks.

05-03-2008, 12:50 AM   #5
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QuoteOriginally posted by gregorygarber Quote
Thanks for posting your shots!

For some reason the "Lens with 1.5x TC, 1/750th, Lens at F8" sticks out at me. Maybe it's the clarity of the "for PENTAX" text at the bottom of the image.

Overally, have you seen much IQ degradation with the TC's?
QuoteOriginally posted by thePiRaTE!! Quote
Very good, thanks for this. The lens seems very clear indeed. I also noted the clarity of the 1.5x f8 shot as Gregory mentioned. It seems its perhaps just slightly more magnified (box was perhaps a little less than 50% farther back).

Shots bode well for the 1.5 and the lens in general, I'd certainly not hesitate to buy based on your test, except I don't use the focal range enough to justify it personally.

Kelly.
Hi Gregory and Kelly, I see what you mean re the "Lens with 1.5x TC, 1/750th, Lens at F8" shot. Reflecting on this test I've learnt quite a bit. Although I tried to move the boxes away from the camera so their image would fill roughly the same area of frame this was far from exact and it would have been better to set the new distances using a tape measure. Also the boxes for the 1.5x TC test are not as square on to the camera/lens as the other shots are (surprisingly difficult to get right), so perhaps the slightly altered angle is also a factor, though I wouldn't think it would make a significant difference to the sharpness.

Overall, I'm happy with IQ using the TC's Gregory. There is inevitably some degradation but I think the lens with TCs is capable of giving good results. I am trying to get into bird photography so I expect to be using it with TCs quite a bit. The 2x test shots appear to show more degradation than the 1.5x but the images taken with the 2x are slightly "closer"/more magnified so this may contribute a little. I have not taken many shots with the 1.5x yet but you can see a couple of bird shots taken with the lens plus 2x TC here:

https://www.pentaxforums.com/forums/post-your-photos/26171-few-birds-da-300-a.html

I'll be taking some more with the 1.5x TC soon as I want to experiment more with the SDM focusing. The 1.5x gives me SDM, whereas with the 2x I have to use manual focusing.

Paul

QuoteOriginally posted by hrishi Quote
Channeler,

Good test.

Does the lens have a tripod mount? I have a very very older (perhaps the 1st version) of Pentax 300/4..It doesnt have a tripod mount n I'm thinking of ways in which it can be mounted on tripod without risking my k10d as well as the lens..

thanks.
Hi Hrishi, Thanks. Yes the lens comes with a tripod collar which is removable. If the barrel size of your lens is similar perhaps you could order a tripod collar from Pentax.

Paul

Last edited by channeler; 05-03-2008 at 01:37 AM.
05-03-2008, 01:43 AM   #6
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When using my K10D or *ist DS with a long lens on the tripod I avoid any shake by setting a short delay (couple of seconds) and firing the shutter with an infra -red trigger. This way you don't actually touch the set-up at all on firing the shutter.
05-03-2008, 07:03 AM   #7
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I was intrested in your comment Paul

Also camera settings were at Sharpness +2 and Contrast +1. I have had the camera permanently on these settings following advice in a Review when I first bought it.

Do you remember the subject to what you have quoted


cheers
05-03-2008, 07:22 AM   #8
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QuoteOriginally posted by hrishi Quote
Channeler,

Good test.

Does the lens have a tripod mount? I have a very very older (perhaps the 1st version) of Pentax 300/4..It doesnt have a tripod mount n I'm thinking of ways in which it can be mounted on tripod without risking my k10d as well as the lens..

thanks.
Good test image Paul. A fine lens for sure.

Hrishi, I bought one of these for that very same lens Support Collar for SMC Pentax 300 mm 1:4 ,FA 300 1:4.5 - eBay (item 230239184109 end time Apr-08-08 22:38:02 PDT)
Not perfect but will hold the lens securely on a tripod. I think the guy makes them himself and would be worth watching or sending him an email to see when he'll have more.

05-03-2008, 07:34 AM   #9
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QuoteOriginally posted by Alan Quote
When using my K10D or *ist DS with a long lens on the tripod I avoid any shake by setting a short delay (couple of seconds) and firing the shutter with an infra -red trigger. This way you don't actually touch the set-up at all on firing the shutter.
Hi Alan, I used a cable release and didn't touch the camera/lens at time of releasing the shutter but noticed a judder. Not sure if it would make any difference using the IR remote. I have one. Probably due to the mirror movement, etc along with the not so solid surface. Under the circumstances probably the only way to overcome this would have been to lock up the mirror.

Paul

QuoteOriginally posted by cupic Quote
I was intrested in your comment Paul

Also camera settings were at Sharpness +2 and Contrast +1. I have had the camera permanently on these settings following advice in a Review when I first bought it.

Do you remember the subject to what you have quoted


cheers
Hi cupic, the Review I read is still online at:

DCRP Review: Pentax K10D

I did do a few of my own tests when I first bought the K10D and felt the reviewer was probably right. I guess it's all down to subjective evaluations at the end of the day. I know some people prefer to keep the camera on the default settings and adjust things afterwards in PP if they feel it is necessary. Personally I'm not keen on spending too much time in PP unless I have to.

Paul

Will be doing some more tests with the DA*300 and the Kenko Teleplus 1.5x DG TC soon especially as regards SDM focusing.

Paul
05-03-2008, 07:38 AM   #10
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Thanks Peter. Going to see how the Lens with 1.5x copes with SDM focusing on birds, static and in flight, next.

Paul
05-03-2008, 11:45 AM   #11
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Hi Paul,

first of all, I much appreciate the great work you did with these samples.

I put them under some pixel-peeping and come to the following personal conculsions:
  • Generally, the DA 300 is very sharp from f/4 on.
  • With TCs, IQ slightly improves when stopping down. At f/8, the TCs don't seem to degrade IQ at all.
  • The Kenko 1.5x and 2x seem to give the same level of IQ (at f/8). At f/4, they are both weaker than the DA300 alone.

The sometimes "clearer" crops seem to come from brighter exposures. I tried to minimize the influence of noise from darker exposures in my conclusion.


My personal verdict would be that, for maximum resolution, I would
  • Not mind to use the DA300 fully open at f/4.
  • Stop down to f/5.6 with 1.4x.
  • Stop down to f/8 with 2x.
This is for tripod mount situations.

However, if light does not permit the apertures mentioned above, I would refrain from using a TC at all because the shake reduction isn't effective with a TC anymore (it gains you only 1 stop anymore -- as opposed to 3-4 stops).
05-03-2008, 12:00 PM   #12
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Technical note

QuoteOriginally posted by channeler Quote
view each image at 100% and then did a crop of the image. If this isn't the right procedure please let me know.
Let me quickly explain what I (and others, I guess) mean by 100% crops... Never mind, you did it right. Thanks again.

The image out of the K20D is 4608x3072 pixels large. When you upload to the forum however, it will resample to a smaller size. By resampling the imformation at the pixel level gets destroyed. Therefore, the practice is to crop the image to such a small piece (700px wide or so) that the forum doesn't resize anymore.

In order to do so, it isn't actually necessary to view the image at 100% when doing the crop. The only point is that it should be small enough afterwards without doing any resizing.


With a TC, it may aditionally be useful to compare a 140% crop of the image w/o a 1.4x TC against a 100% crop with TC, i.e., digital vs. optical zoom. This is the only way to know whether the TC gives you anything extra compared to a bicubic resize of the image in Photoshop or so.

Below is such an example I did with K20D + Tamron 1.4x + DA* 50-135. Note that I failed to have equal exposure (i.e. different noise) because I didn't plan it as a test. But you get the idea...

(BTW: Which side is which, and ignore the noise... ?)

Last edited by falconeye; 06-15-2011 at 05:27 AM.
05-03-2008, 01:19 PM   #13
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Squirrels across the pond........

Well, Paul, here's a US friend for your UK buddy..........DA* 300mm, from about 25yds., handheld from my balcony a bit ago.......about a 100% crop......



Flickr Photo Download: West Virginia Grey
05-03-2008, 02:55 PM   #14
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QuoteOriginally posted by channeler Quote
Thanks for the source. The sentence you have been referrering to reads: "JPEG at +2 sharpness, +1 contrast [...] is probably where I'd leave things if I owned the K10D"

The K20D is known for its much improved JPEG rendition. We still have to figure out optimal settings here, I guess. Speaking for myself, I haven't yet
05-03-2008, 03:04 PM   #15
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QuoteOriginally posted by John Kovarik Quote
Well, Paul, here's a US friend for your UK buddy..........DA* 300mm, from about 25yds., handheld from my balcony a bit ago.......about a 100% crop......
Another friend from the continent, heavy crop from 70mm. Now you see why I need the 300mm

Last edited by falconeye; 06-15-2011 at 05:27 AM.
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