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cooltouch
Joined: 15 Jan 2009 Posts: 9096 Location: Houston, Texas
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Posted: Wed Dec 28, 2011 4:16 am Post subject: Crescent Moon -- Refractor vs. Reflector |
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cooltouch wrote:
Tonight's crescent moon made for a great photo subject, and a perfect opportunity for me to test a recent purchase of mine, a Tamron 55BB SP 500mm f/8 against a tried-and-true old refractor I own, a manual aperture T-mount Century Precision Optics 500mm f/5.6. I've had very good results shooting images of the moon with my CPO 500, several of which I've posted here, but tonight's the first time I've tried shooting the moon with my Tamron. In fact, this is the first time I've ever done any sort of critical comparison with it.
Honestly, I figured that, despite its age, the CPO 500 would show the superiority in contrast and sharpness that's almost always the case when a refractor is compared to a reflector. But as the two following photos show, the differences are much less than I would have thought. No sharpening was done with either image, although I did adjust contrast somewhat, mostly to the CPO's photo.
CPO 500mm f/5.6 @ f/8
Tamron 500mm f/8
I've combined the two images so it's easier to compare the two optics:
In retrospect, I probably should have left the contrast alone with the CPO's image because it does show to be contrastier than the Tamron's. But I took the CPO's photo earlier, when the skies were quite a bit brighter. I should have reduced exposure also. You'll note that there's some burn-through in the CPO's image along the edge of the moon. The image as shot was rather gray looking so I adjusted it by bumping up the contrast until the skies were about the same level of darkness as the Tamron's. The difference in skies also accounts for the difference in colors seen. The CPO's has a bit of a yellowish tinge, which was caused by the sky's sunset colors. By the time I shot with the Tamron, the moon's colors were dominant.
As you can see, sharpness wise, the two images are very close. The CPO just barely edges out the Tamron in sharpness. Take a look at the crater toward the bottom of the photos that has a small peak in the center. This crater has a double wall, which is well defined in both photos, but is just a bit better defined in the CPO's photo. Nonetheless, I was really surprised by just how much detail I was able to capture with the Tamron. And even though the Tamron mirror has almost a 360 degree throw to its focusing collar, its focusing is still very touchy at infinity. So given this touchiness, it is very possible that I may have missed optimum focus by just a bit, so who's to say?
Which lens is the sharper? Welp, I must conclude that this test is not conclusive enough to say. So, I'll have to do a retest. Oh, goody!
_________________ Michael
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iangreenhalgh1
Joined: 18 Mar 2011 Posts: 15679
Expire: 2014-01-07
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Posted: Wed Dec 28, 2011 4:33 am Post subject: |
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iangreenhalgh1 wrote:
Nice shots, I do prefer the CPO one, probably more because it's more coloured than anything else as they are very close in IQ. _________________ I don't care who designed it, who made it or what country it comes from - I just enjoy using it! |
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s58y
Joined: 05 Sep 2010 Posts: 131 Location: Eastern NY
Expire: 2013-09-10
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Posted: Wed Dec 28, 2011 7:02 am Post subject: |
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s58y wrote:
Nice shots. I've always have a hard time getting the best focus on moonshots. Atmospheric turbulence makes the details you're focusing on move around in magnified liveview, so you never know quite where to stop. _________________
flickr photostream
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IAZA
Joined: 16 Apr 2010 Posts: 2587 Location: Indonesia
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Posted: Wed Dec 28, 2011 11:31 am Post subject: |
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IAZA wrote:
I thought you have not god copy of Tamron 500, you mentioned in earlier post after you bought that tammy.
or I miss something?
the CPO shot is great, butI like result of tamron too _________________ nex5, Olympus EPM1, yashica half 14, Canon eos 650 want to see samples of mine? please click My lenses
and My gallery
~Suat~ |
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Smoli4
Joined: 01 Jul 2011 Posts: 606 Location: Haifa, Israel
Expire: 2013-06-07
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Posted: Wed Dec 28, 2011 1:26 pm Post subject: |
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Smoli4 wrote:
with camera did you shot with? cause i have two russion mirros, and i can crop to the same resulution , and compare one of my moon shots. |
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yinyangbt
Joined: 08 Oct 2010 Posts: 1973 Location: Romania
Expire: 2012-12-27
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Posted: Wed Dec 28, 2011 2:02 pm Post subject: |
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yinyangbt wrote:
It seems to me that the CPO is sharper . The tamron seems less contrasty and softer .It doesn't seems to me that you lost something in that slightly burned edge of the moon , at least the tamron image doesn't show some more detail there. _________________ Cheers , Teo
http://photo.net/photodb/member-photos?user_id=5778915 |
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cooltouch
Joined: 15 Jan 2009 Posts: 9096 Location: Houston, Texas
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Posted: Wed Dec 28, 2011 5:48 pm Post subject: |
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cooltouch wrote:
s58y wrote: |
Nice shots. I've always have a hard time getting the best focus on moonshots. Atmospheric turbulence makes the details you're focusing on move around in magnified liveview, so you never know quite where to stop. |
That's why I always shoot multiple exposures of the same scene. Surely at least one will be critically sharp. I winnowed through seven shots with the CPO and five shots with the Tamron to arrive at the two I selected for inclusion here. _________________ Michael
My Gear List: http://michaelmcbroom.com/photo/gear.html
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cooltouch
Joined: 15 Jan 2009 Posts: 9096 Location: Houston, Texas
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Posted: Wed Dec 28, 2011 5:50 pm Post subject: |
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cooltouch wrote:
IAZA wrote: |
I thought you have not god copy of Tamron 500, you mentioned in earlier post after you bought that tammy.
or I miss something?
the CPO shot is great, butI like result of tamron too |
You didn't miss anything. Sorry for the confusion. I still have the 55B, which is the one with the element separation problem. I found this 55BB a few months ago, sitting in the case at a local camera shop. I dunno what I'm going to do with the 55B, probably sell it "as is" on eBay. _________________ Michael
My Gear List: http://michaelmcbroom.com/photo/gear.html
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cooltouch
Joined: 15 Jan 2009 Posts: 9096 Location: Houston, Texas
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Posted: Wed Dec 28, 2011 5:52 pm Post subject: |
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cooltouch wrote:
Smoli4 wrote: |
with camera did you shot with? cause i have two russion mirros, and i can crop to the same resulution , and compare one of my moon shots. |
I shot with a 10.1 mp Canon XS (1000D). It's the only DSLR I have right now.
Sure, I'd be interested in seeing your Russian mirrors' performance. I know that the Russian mirrors have an outstanding reputation, so I would expect good performance. _________________ Michael
My Gear List: http://michaelmcbroom.com/photo/gear.html
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cooltouch
Joined: 15 Jan 2009 Posts: 9096 Location: Houston, Texas
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Posted: Wed Dec 28, 2011 6:01 pm Post subject: |
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cooltouch wrote:
yinyangbt wrote: |
It seems to me that the CPO is sharper . The tamron seems less contrasty and softer .It doesn't seems to me that you lost something in that slightly burned edge of the moon , at least the tamron image doesn't show some more detail there. |
Your observances are the same as mine. But I did boost the contrast considerably with the CPO. It was late dusk, and the sky was not black. Here is the unretouched image -- just cropped and slightly resized for viewing here:
_________________ Michael
My Gear List: http://michaelmcbroom.com/photo/gear.html
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strudelj
Joined: 28 Sep 2011 Posts: 20 Location: Slovenia, Ljubljana
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Posted: Wed Dec 28, 2011 10:14 pm Post subject: |
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strudelj wrote:
Nice moon shots. I would agree with others that the CPO is sharper. But I am biased; I exclusively prefer refractors over reflectors.
But really, most of all shooting something through kilometers of atmosphere is like shooting something through couple of meters of water. I would say that the sharpness of moon images depends more on seeing and atmospherics disturbances, than on quality of the lenses which both seem very good.
Another very important thing, CPO has a surprisingly low CA, especially for a fast f5.6 refractor. Was it stopped down? |
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NewStuff
Joined: 31 Mar 2011 Posts: 847 Location: Wales, UK
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Posted: Thu Dec 29, 2011 1:02 am Post subject: |
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NewStuff wrote:
First shot is the winner for me! Much prefer the overall look it presents.
I need to get my Benbo back, and run off a few moon shots.
Pentacon 300/4+2x TC should do the trick! (My current tripod runs screaming from this combo!) _________________ Too many to list. |
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cooltouch
Joined: 15 Jan 2009 Posts: 9096 Location: Houston, Texas
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Posted: Thu Dec 29, 2011 7:46 pm Post subject: |
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cooltouch wrote:
strudelj wrote: |
But really, most of all shooting something through kilometers of atmosphere is like shooting something through couple of meters of water. I would say that the sharpness of moon images depends more on seeing and atmospherics disturbances, than on quality of the lenses which both seem very good.
Another very important thing, CPO has a surprisingly low CA, especially for a fast f5.6 refractor. Was it stopped down? |
Yes, when I shoot moon shots I always stop it down to f/8 or f/11. However, even wide open this CPO 500 has very little CA, which is surprising, considering it is nothing more that a "well corrected achromatic doublet," according to the past president of CPO, whom I had a chance to talk with shortly after buying the lens some 20 years ago.
I'm glad you mentioned atmospherics, because this is something I neglected to mention. The skies were exceptionally clear, and had been all day. Unlimited visibility, absolutely no atmospheric haze. An astronomer will tell you that clear skies are not always the best for seeing because often there is more atmospheric turbulence, and that "heavy" humid skies with perhaps a bit of haze are often more stable, and thus can result in better photographs, especially planetary ones.
However, when looking through the lens, I saw very little evidence of turbulence -- almost none. So I had the good fortune of clear yet still skies when I was taking these shots. _________________ Michael
My Gear List: http://michaelmcbroom.com/photo/gear.html
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cooltouch
Joined: 15 Jan 2009 Posts: 9096 Location: Houston, Texas
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Posted: Thu Dec 29, 2011 8:17 pm Post subject: |
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cooltouch wrote:
NewStuff wrote: |
First shot is the winner for me! Much prefer the overall look it presents.
I need to get my Benbo back, and run off a few moon shots.
Pentacon 300/4+2x TC should do the trick! (My current tripod runs screaming from this combo!) |
Well it looks like the CPO is eking out the win. Sorry Tamron, ya put up a good fight!
Hey! A fellow Benbo owner! So how long have you owned yours? If yours is old, have your Bembo's feet cups cracked and fallen off yet? I need a replacement set for mine.
Folks, in case you don't know, the Benbo -- now made by Paterson -- is one incredibly adaptable tripod. You can position it anywhere for anything at any angle.
Here's a photo of one I snagged from B&H. Looks just like mine, except the legs are taller.
_________________ Michael
My Gear List: http://michaelmcbroom.com/photo/gear.html
My Gallery: http://michaelmcbroom.com/gallery3/index.php/
My Flickr Page: https://www.flickr.com/photos/11308754@N08/albums
My Music: https://soundcloud.com/michaelmcbroom/albums
My Blog: http://michaelmcbroom.com/blogistan/ |
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NewStuff
Joined: 31 Mar 2011 Posts: 847 Location: Wales, UK
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Posted: Thu Dec 29, 2011 8:32 pm Post subject: |
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NewStuff wrote:
My Benbo is, I think, the MK1, with the 4 way head (I've seen a few trekkers, but never another 4way. I assume they are not common).
I've had it for 5 or so years, the previous owner had it from new, and still enquires about it to this day. He sold it after selling his *big* glass (the 600mm L was something to behold). It';s also dubbed the "Comedy Tripod" because of my propensity to lug it around abandoned buildings, asylums and slate mines, where you are far more likely to find someone using a Slik Mini or similar.
The feet have not cracked, but I do need to repair one of the tightening knobs on the legs. It's the best Macro tripod I have ever owned, and will likely be that way for as long as I can carry it. I wouldn't swap it for the world. _________________ Too many to list. |
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cooltouch
Joined: 15 Jan 2009 Posts: 9096 Location: Houston, Texas
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Posted: Thu Dec 29, 2011 10:17 pm Post subject: |
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cooltouch wrote:
Good on ya. Mine came with an original ball head. I was over at the Paterson site, and determined that mine is most likely a Trekker because of the leg length. The bottom sections are only about 20" long or so. The ball head is what Patterson calls their Compact Ball & Socket Head, which was available with the Trekker models, but it is sturdy enough to support a long telephoto and a fairly heavy camera/motordrive combo. _________________ Michael
My Gear List: http://michaelmcbroom.com/photo/gear.html
My Gallery: http://michaelmcbroom.com/gallery3/index.php/
My Flickr Page: https://www.flickr.com/photos/11308754@N08/albums
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