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05-18-2012, 09:16 PM   #16
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@ Mock, Just had a look at the 112mm Filter on Fleabay and looks very reasonablly priced , considering I just paid $95.0 for a 62 mm Hoya CPL filter.

I've had a Manfrotto 055CLB Tripod for a number of years which I assume to convert to a gimble head is a easy enough process.!? Have had a look on Ebay and there are some nicely made once and some claim are made out of Aircraft grade Alumiumn etc.

Just waiting on my dear friend to get back to me with regards to the Tamron 60B lens' selling price.

05-19-2012, 01:42 PM   #17
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QuoteOriginally posted by Lowell Goudge Quote
Ben

I am interested in your comment about the front filter also adding to the sharpness. Go back a couple of pages in the 300 mm lens forum and you will see a shot I took with my 200-500/5.6 and some flare/reflections

I still need to track down the cause but I am leaning towards the Tamron front filter. I would be interested in your comments
Lowell, I think the reason for the improved sharpness was quite simply, that the 60B is not an Apo lens. The front filter will reduce excessive far blue and UV light, which would otherwise be focused differently from the rest of the visible spectrum and lead to some blurriness superimposed on the image, which equals a considerable loss of contrast. As contrast is a decisive factor, when it comes to perceived sharpness, this loss (without filter) or improved contrast will also improve the apparent sharpness of the lens. This was at least the conclusion from the thread

Here is the original discussion: Legacy Lenses Tamron SP 300mm f2.8 LD IF

Mock: your findings of improved contrast with the filter in place, would support these older findings. Also, you are quite right: the lens shade of the 60B is very effective and thus the added two glass surfaces of the filter won't usually do any harm, provided the filter is of high quality.

The front filter will also slightly affect the focus of the lens, but that is negligible. The focus will be shifted by a tiny amount and I guess, that this is not really noticeable.

Ben
05-19-2012, 02:37 PM   #18
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QuoteOriginally posted by Ben_Edict Quote
The front filter will reduce excessive far blue and UV light,
I tend to agree with Ben's statement although I have no credible evidence to substantiate that rational other than occasional observation in the field. When high UV is present, additional UV filtration seems to make a noticeable difference in contrast that appears as 'sharpness' when focusing over long distances -- I don't see the same effect at close-up distances.

H2
05-20-2012, 05:21 AM   #19
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QuoteOriginally posted by disco_owner Quote
@ Mock, Just had a look at the 112mm Filter on Fleabay and looks very reasonablly priced , considering I just paid $95.0 for a 62 mm Hoya CPL filter.

I've had a Manfrotto 055CLB Tripod for a number of years which I assume to convert to a gimble head is a easy enough process.!? Have had a look on Ebay and there are some nicely made once and some claim are made out of Aircraft grade Alumiumn etc.

Just waiting on my dear friend to get back to me with regards to the Tamron 60B lens' selling price.
The 055 is a time-proven tripod and I converted one of those myself to use the Manfrotto gimbal head. The 055 sprots a standard 3/8''-screw, which will fit almost any tripod head. By the way, whether the gimbal is made of "aircraft grade" aluminium is not the decisive factor. The much more important consideration is, whether it moves freely and smoothly around its pivot points. Also a gimbal really needs a good tension setting, otherwise it is nor really useful.

Ben

05-20-2012, 06:14 AM   #20
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QuoteOriginally posted by disco_owner Quote
Friend has a Tamron 300 2.8 for sale , I'm rather interested in the lens but not sure which version it is so I need some clarification.
FWIW There are at least three manual focusing versions of this lens , The conventional focusing versions labeled Tamron SP 300mm f2.8 LD, and the two internal focusing versions, labeled Tamron SP 300 mm f2.8 LD IF. Apparently The two IF versions are the olive green model 60B ?

would there be an advantage in buying the IF version in that it would make focusing easier . is there also a need for a Katzeye or Split screen of a K-5 . my eye sight has given up the ghost so any aid would be helpful.
Save yourself some grief and get the DA300 f4 (Had both DA and 360b)
05-20-2012, 02:59 PM   #21
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QuoteOriginally posted by borno Quote
Save yourself some grief and get the DA300 f4 (Had both DA and 360b)
I hear ya, It looks like I may be going that way Borno. he has not contacted me regarding the lens so I don't know if he wants to part with the lens.

also by the time I weight up the Gimble head for the Tripod , the accessories for the lens ( filters etc ) and Teleconverters it's not worth the coins, knowing he would not want part with the lens at a cheaper price.

so back to the drawing board.
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