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12-30-2010, 11:35 AM   #16
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Well I've been trying to find some of the suggested lenses on here but all of them seem to be about 200 and above.
So far the cheapest I've found a Tamron 90mm for is 295, is there something I'am missing here or are lenses just damn expensive here in the UK?

12-30-2010, 11:38 AM   #17
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QuoteQuote:
...However, the Raynox 150 and 250 are respectively +4.8 and +8 diopters and the DoF, of the 250 especially, is very shallow - the greater the magnification of the lense (e.g. a macro lense) the shallower the DoF when adding the Raynox to it....
Here's an experimental result showing that macros shot with a closeup lens added to a primary lens have the same depth of field as those shot with a dedicated macro lens (when the actual f-numbers are the same.)

The camera was set up to shoot a blank laptop screen at an angle of about 30 degrees from normal. DoF is shown by the width of the in-focus stripe (each square in the stripe is about 0.25mm wide).


The in-focus depth for the Raynox DCR 150 close-up lens on a DA 55-300mm, f:8 lens zoomed to a 1:1 magnification ratio is about the same as that for a Macro-Takumar 50:4 lens at 1:1 magnification ratio, f:4. The f-number of the close-up/zoom lens arrangement was adjusted to be the same as that for the macro lens (divide nominal f-number by (1+magnification)).

I hope this clarifies the effect of Close-up lenses on the DoF for macros,

Dave
12-30-2010, 11:57 AM   #18
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QuoteOriginally posted by kaimarion Quote
Well I've been trying to find some of the suggested lenses on here but all of them seem to be about 200 and above.
So far the cheapest I've found a Tamron 90mm for is 295, is there something I'am missing here or are lenses just damn expensive here in the UK?
The Cosina 100mm 1:3.5 and the Pentax-M 100mm 1:4 should be much cheaper than that, they are no longer made and consequently can be had second-hand only (although a NIB Cosina may pop-up sometimes). Currently, there seems to be a Pentax-M going on ebay.co.uk for a reasonable price: Pentax-M Macro 100mm f4, SMC, PK bayonet, mint- on eBay (end time 27-Jan-11 18:54:51 GMT)
12-30-2010, 12:03 PM   #19
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QuoteOriginally posted by newarts Quote
Here's an experimental result showing that macros shot with a closeup lens added to a primary lens have the same depth of field as those shot with a dedicated macro lens (when the actual f-numbers are the same.)

The camera was set up to shoot a blank laptop screen at an angle of about 30 degrees from normal. DoF is shown by the width of the in-focus stripe (each square in the stripe is about 0.25mm wide).


The in-focus depth for the Raynox DCR 150 close-up lens on a DA 55-300mm, f:8 lens zoomed to a 1:1 magnification ratio is about the same as that for a Macro-Takumar 50:4 lens at 1:1 magnification ratio, f:4. The f-number of the close-up/zoom lens arrangement was adjusted to be the same as that for the macro lens (divide nominal f-number by (1+magnification)).

I hope this clarifies the effect of Close-up lenses on the DoF for macros,

Dave
Careful. Only the earliest 50 Takumar macro is 1:1 per the lens database. Most found will be the later 1:2 versions.

S-M-C/Super Macro-Takumar 50mm F4 Lens Reviews - Pentax Lens Reviews & Pentax Lens Database



12-30-2010, 12:08 PM   #20
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QuoteOriginally posted by JeffJS Quote
Careful. Only the earliest 50 Takumar macro is 1:1 per the lens database. Most found will be the later 1:2 versions.

S-M-C/Super Macro-Takumar 50mm F4 Lens Reviews - Pentax Lens Reviews & Pentax Lens Database

I used a Genuine Macro-Takumar 50:4 1:1 in the test reported above. The original version! It is a nice little lens with two aperture rings on the front.
12-30-2010, 12:29 PM   #21
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Vivitar/Panagor 55mm or 90mm. Search the lens database. Should go for about $150 max! And they are great!!!
12-30-2010, 12:33 PM   #22
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QuoteOriginally posted by newarts Quote
I used a Genuine Macro-Takumar 50:4 1:1 in the test reported above. The original version! It is a nice little lens with two aperture rings on the front.
It is indeed a great little lens (I have both it and the SMC 1:2 version as I loved them so much). Actually, I would recommend that the OP look at the Pentax-M 50mm f4, which is that same optic as the Takumar versions (really wonderful, actually my favorite lens), as that lens is a wonderful optical performer, is small, light, and very cheap (in the U.S., $75-125 or so). The only downside is that it only focuses down to 1:2, but the OP may not one to get even closer (I find myself only very rarely taking pictures at magnification greater than 1:2, as the DOF gets so small and a tripod starts really becoming more needed).
12-30-2010, 12:37 PM   #23
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QuoteOriginally posted by newarts Quote
Here's an experimental result showing that macros shot with a closeup lens added to a primary lens have the same depth of field as those shot with a dedicated macro lens (when the actual f-numbers are the same.)

The camera was set up to shoot a blank laptop screen at an angle of about 30 degrees from normal. DoF is shown by the width of the in-focus stripe (each square in the stripe is about 0.25mm wide).


The in-focus depth for the Raynox DCR 150 close-up lens on a DA 55-300mm, f:8 lens zoomed to a 1:1 magnification ratio is about the same as that for a Macro-Takumar 50:4 lens at 1:1 magnification ratio, f:4. The f-number of the close-up/zoom lens arrangement was adjusted to be the same as that for the macro lens (divide nominal f-number by (1+magnification)).

I hope this clarifies the effect of Close-up lenses on the DoF for macros,

Dave
That was quick. I still have the thread open in another tab but due to the holidays haven't had a chance to address it !

Thank you for doing the test .. it's very interesting. However there are two notable issues a) even from the test shot posted there is a distinguishable difference in the DoF. At both ends of the range !
b) when you add a diopter / Raynox you have indeed changed the FL so a test based on a DoF analysis at the same FL (with and then without the Raynox) is actually not a real life scenario. In practice the DoF is much narrower because the FL has changed substantially.

I do appreciate you doing these tests though - I'm learning a lot from you.

12-30-2010, 01:30 PM   #24
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I picked up a Vivitar 55 f2.8 with a 1:1 macro capability for $110 on flebay a few weeks ago. It is used but might as well be NOS as it is perfect. This lens is amazing and I would recommend it very highly. It's fast, and at 55mm small and light compared to many of the others while offering around 82mm on a crop sensor which is great for general photos. Only down side is that at 1:1 you have to be quite close to the subject. I took it to the conservatory at the St. Paul Zoo and was able to use it as my only lens with great shots of family and quick transitions to macro for flower / fern shots etc...
12-30-2010, 01:36 PM   #25
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QuoteOriginally posted by Rense Quote
Vivitar/Panagor 55mm or 90mm. Search the lens database. Should go for about $150 max! And they are great!!!
QuoteOriginally posted by indy Quote
I picked up a Vivitar 55 f2.8 with a 1:1 macro capability for $110 on flebay a few weeks ago. It is used but might as well be NOS as it is perfect. This lens is amazing and I would recommend it very highly. It's fast, and at 55mm small and light compared to many of the others while offering around 82mm on a crop sensor which is great for general photos. Only down side is that at 1:1 you have to be quite close to the subject. I took it to the conservatory at the St. Paul Zoo and was able to use it as my only lens with great shots of family and quick transitions to macro for flower / fern shots etc...
So that are two!!!
12-30-2010, 01:46 PM   #26
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QuoteOriginally posted by Rense Quote
So that are two!!!
There are at least three.

This is one of my favorites. It's a bit rare, but you may get lucky.

Its mag. ratio is only 1:2 but at 20 inches, it provides plenty of space for little creatures being photographed.

12-30-2010, 02:07 PM   #27
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QuoteOriginally posted by newarts Quote
I used a Genuine Macro-Takumar 50:4 1:1 in the test reported above. The original version! It is a nice little lens with two aperture rings on the front.
I completely understand that you know what you have but for the benefit of those who don't know, I thought it worth pointing out. Until 60 seconds before I made that post, I was one of the people who didn't know there was a 1:1 version of the lens .

12-30-2010, 02:17 PM   #28
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The 90mm Pangor will give you more distance from the subject, but be ready for an exponential increase in size and weight!
12-30-2010, 03:57 PM   #29
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QuoteOriginally posted by Frogfish Quote
...
a) even from the test shot posted there is a distinguishable difference in the DoF. At both ends of the range !
I'm happy the results came out as good as they did. DOF tests are not easy to do with limited equipment.

I think it is fair to say the result is consistent with the prediction that DoF is independent of the lens used and depends on actual f-number and magnification. The result is not consistent with the prediction that using a Raynox causes a very small DOF.

QuoteQuote:
b) when you add a diopter / Raynox you have indeed changed the FL so a test based on a DoF analysis at the same FL (with and then without the Raynox) is actually not a real life scenario.
I'm not sure what you mean, I used widely different focal lengths to emphasize the point that focal length isn't the main variable involved. Do you want a test where one lens is a 50mm macro lens and the other lens has been turned into a 50mm by adding a Raynox?

QuoteQuote:
In practice the DoF is much narrower because the FL has changed substantially.
That's not the whole story; the FL has changed causing the f-stop to change. It is the f-stop change that results in the DoF change. The DoF can be modified by turning the aperture ring if you like.

This is an important point. When a Raynox or other diopter is used to increase a lens' magnification to m, the f-stops are also changed by a factor of 1/(1+m).

Say that a Raynox 250 (125mm) is added to a 125mm, F16 lens; that lens is changed to a 62.5mm, F8 lens (the "16" mark on the lens barrel now means "8")*.

QuoteQuote:
I do appreciate you doing these tests though - I'm learning a lot from you.
Thanks, I enjoy trying to make theory useful.

*edit: this may in theory limit the maximum DoF obtainable. For example, maximum f-stop of the DA 55-300 is F:22 - when the Raynox is added and the magnification is adjusted to 1:1, the actual maximum f-stop is F:11. On the other hand, the Macro-Takumar's maximum f-stop is F:22, so it can in theory have twice the DoF as the zoom with Raynox (these are hypothetical numbers because diffraction problems set in at about actual_f-stop*(1+m) ~16- 20 for a K-x, therefore both lenses should have about the same DoF capability at 1:1.)

Last edited by newarts; 12-31-2010 at 06:13 AM.
12-31-2010, 03:59 AM   #30
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QuoteOriginally posted by indy Quote
I picked up a Vivitar 55 f2.8 with a 1:1 macro capability for $110 on flebay a few weeks ago. It is used but might as well be NOS as it is perfect. This lens is amazing and I would recommend it very highly. It's fast, and at 55mm small and light compared to many of the others while offering around 82mm on a crop sensor which is great for general photos. Only down side is that at 1:1 you have to be quite close to the subject. I took it to the conservatory at the St. Paul Zoo and was able to use it as my only lens with great shots of family and quick transitions to macro for flower / fern shots etc...
Indy, do you have any photos from this lens uploaded online? I have the DA35Ltd macro and a 105mm Lester, but a 50 - 70 mm macro could see some use at times.

QuoteOriginally posted by SOldBear Quote
There are at least three.

This is one of my favorites. It's a bit rare, but you may get lucky.

Its mag. ratio is only 1:2 but at 20 inches, it provides plenty of space for little creatures being photographed.
Hmm, due to the praise sung to that lens here on the forums I tried to find a copy at decent price for over a year without luck.
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