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08-04-2016, 10:39 PM   #1
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Macro & close up

Hi folks

I'm looking for a good macro or close up lens (focus < 40cm) for my P-645N II / 645D . Any suggestions/idee's?

Daniel


Last edited by sugus; 08-04-2016 at 10:46 PM.
08-04-2016, 11:36 PM   #2
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A120 f4 macro is highly recommended and most affordable compare to others.


marcus
08-04-2016, 11:57 PM   #3
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I know but the focus is 1.3 feet (0.39m).

I'm looking for a "closer" focus....... Perhaps from another brand?

Daniel
08-05-2016, 02:26 AM   #4
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QuoteOriginally posted by sugus Quote
I know but the focus is 1.3 feet (0.39m).

I'm looking for a "closer" focus....... Perhaps from another brand?

Daniel
67 100 f4 with adapter and mount extension tube will give a very short working distance.

Need a 67 ton645 adapter in m mode


Marcus

08-05-2016, 02:45 AM   #5
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QuoteOriginally posted by sugus Quote
I know but the focus is 1.3 feet (0.39m).


Daniel
Just making sure that you're aware that the 39cm minimum focus distance of the 120/4 is measured from the film/sensor plane and that the distance to the end of the lens barrel (the working distance) is only 14cm (5-1/2").

Bob
08-05-2016, 03:56 AM   #6
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I like the 120/f4 very much - it has become my usual lens on the 645n. In action with XP2:




Chris
08-05-2016, 04:46 AM   #7
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[/COLOR]
QuoteOriginally posted by drmoss_ca Quote
I like the 120/f4 very much - it has become my usual lens on the 645n. In action with XP2:


Chris
Is this "free hand"?
08-05-2016, 11:59 AM   #8
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QuoteOriginally posted by sugus Quote
I know but the focus is 1.3 feet (0.39m).

I'm looking for a "closer" focus.
So, use the 120 with tubes.

08-05-2016, 12:36 PM   #9
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The 120mm does 1:1, no? How much magnification do you need?
08-05-2016, 03:04 PM   #10
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Yes the A120 does 1:1 magnification and at max magnification the working distance is approx. 5 to 6 inches between the front barrel of the lens to the subject. putting a set of extension tubes will bring the working distance much near, with almost doubling the magnification, but there will be a loss of light.

marcus
08-06-2016, 08:30 AM   #11
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Not sure if the Pentax 645 systems has them, but close-up lens attachments are an option and I use them for my 6x7 system. There is no light loss like you get using extension tubes and there are no TTL/AE metering issues.

You can get pretty close with them and they improve the close focusing of most normal/short telephoto lenses.

Phil.
08-06-2016, 12:56 PM   #12
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QuoteOriginally posted by gofour3 Quote
.........There is no light loss like you get using extension tubes and there are no TTL/AE metering issues.
Is this an often repeated myth or is there some validity to it.....for every dissenting statement there seem to be tens if not hundreds of concurring ones.
I've resorted to the text books once again and the maths and physics would seem to disagree with the "no light loss" side of the debate.

Adding a diopter/close up filter effectively increases the focal length of the native lens (otherwise there would be no increase in magnification). If the focal length has increased then the entrance pupil diameter must also increase if the f-stop ratio is to remain the same....clearly the entrance pupil diameter can't increase so the f-stop ratio must decrease by an amount proportional to the increase in focal length.

To quote an article in Cambridge in Colour;
"(A diopter) Retains more light at a given f-stop setting when compared to extension tubes (since the effective aperture no longer increases). However, when both are set to the same depth of field and magnification, both capture roughly the same amount of light".
( Macro Extension Tubes & Close-up Lenses )

Bob
08-06-2016, 03:25 PM   #13
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QuoteOriginally posted by Bob L Quote
Is this an often repeated myth or is there some validity to it.....for every dissenting statement there seem to be tens if not hundreds of concurring ones.
I've resorted to the text books once again and the maths and physics would seem to disagree with the "no light loss" side of the debate.

Adding a diopter/close up filter effectively increases the focal length of the native lens (otherwise there would be no increase in magnification). If the focal length has increased then the entrance pupil diameter must also increase if the f-stop ratio is to remain the same....clearly the entrance pupil diameter can't increase so the f-stop ratio must decrease by an amount proportional to the increase in focal length.

To quote an article in Cambridge in Colour;
"(A diopter) Retains more light at a given f-stop setting when compared to extension tubes (since the effective aperture no longer increases). However, when both are set to the same depth of field and magnification, both capture roughly the same amount of light".
( Macro Extension Tubes & Close-up Lenses )

Bob
I mean no light loss as you do not need to compensate an exposure factor as you would for extension tubes or with a close focused macro lens.

See the Pentax 6x7 close-up lens manual on page one:

6X7 CLOSEUP LENSES

Phil.
08-07-2016, 04:11 AM   #14
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QuoteOriginally posted by sugus Quote
[/COLOR]

Is this "free hand"?
I used a monopod.

Chris
08-07-2016, 04:42 AM   #15
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The Raynox Macro Explorer kit comes with two achromatic close-up lens units. One reduces lens-to-subject distance to about 8 inches, the other to about 4 inches, with the lens set to infinity (slightly closer when lens is focused closer). The included quick-mount attaches these to lenses with 52 to 67mm filter threads. My controlled tests of Raynox lenses compared to extension tubes and dedicated close-up lenses indicates that if mounted on a good quality SFL lens they provide IQ essentially indistinguishable from tubes, and very close to the quality of a dedicated macro lens. One unpredictable: with some lenses there is vignetting, for example, there was no vignetting with the Raynox + DA 70mm f2.4, but there was substantial vignetting at every focal length when mounted on a Sigma 17-70 zoom. Granted I was testing on APS-C, and there might be severe vignetting when the Raynox is used on 645. However, if you are trying to achieve extreme close-up (probably greater than 1:1 when mounted on a normal focal length 645 lens) any vignetting will be cropped off anyway as you only want the central image.

The Raynox are well worth considering, especially if you can experiment with them at some local camera store. At only $110, they are by far the least expensive. most convenient route to good, even excellent quality macro.
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