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Getting more than 1:1 macro from 1:1 lenses

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How does one get greater magnification than 1:1 from a lens that only focuses down to 1:1? Teleconverters? Diopters? Some combination?

 

The lenses I'm specifically interested in doing this with are:

Canon 100mm macro

Sigma 50mm and 150mm macro

 

Will the same technique work equally well with all three (and others)?

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Hi Bruce,

 

Both teleconverters and diopters will help increase magnification. Teleconverters maintain working distance, but steal light. So an f2.8 50mm lens with a 1.4x TC becomes a 70mm f4 lens.

 

Diopters decrease working distance but don't steal any light. They are effective with lenses which start with a long working distance. Shorter working distance lenses like the 50mm do not benefit from the diopter as you don't have enough working distance to make a photo (the close focus is literally inside the port...lol). There are wet diopters that mount on the outside of the port and dry diopters that mount on the lens. There are achromat (multiple element) diopters which are better than the single element type because they reduce chromatic aberration (spelling???).

 

HTH

James

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The extension tubes will allows closer focusing resulting in higher magnification, this without loss of opticall quality but the drawback is proximity, you end up being much closer so use only with longer focal lenght.

 

James: go back to bed, you are a newly wed and should still be trying to reproduce (or at least pretend to) :)

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THis subject is of interest to me - I've been shooting various combinations of TCs and diopters, but I've never tried an extension uw. My understanding of extension is that the degree of magnification depends on the ratio of the extension to the native focal length. In other words, a short lens like a 60mm would get double magnification (100%)when used with a 60mm extension, but that same extension would only give 60% improvement when placed behind a 100mm. Hence, I thought that extension worked best with shorter focal lengths. Am I incorrect here? What specific combinations of lenses and extensions have you guys used? What degree of magnification have you achieved?

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I've been working a little with the 2xTC on my 105mm. Never really had it on where the conditions were perfect as the magnification doesn't allow much in the way of water movement. And, I've ended up with lots of junk as well, but it's great when it works. Shot this in Florida a couple weeks ago:

 

tiffDSC_3489_ctworm1-01_700.jpg

 

Rand

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Rand,

 

Cool!

 

Which 2X are you using? I haven't found many choices for Nikon AF (vis a vis AF-S) lenses.

 

Thanks,

Chris

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(Nice shot, Rand!)

 

A TC question. My recollection is that Canon's 1.4x and 2x TC's only work with their L series lenses. What TC's are usable with Canon's non-L and/or more generic (e.g., Sigma) lenses?

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Kasey, the 60mm has a built in "extension" to attain 1:1 so if I remember well, somewhere around 30mm should give you the 2:1, but hey, I could be wrong on that one, any engineer want to coraborate or demolish this theory. :D

 

The way I figure the lens and a 60mm tube would give you 1:1 if the focus was left at infinity... :)

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I assume that using an extension tube costs you some light (you're adding a small dark tunnel) - any rule of thumb as to how MUCH light you forfeit?

 

And if you can double the magnification with an extension tube, why would anyone use a 2X TC, which has a (significantly) higher price, and which introduces extra glass and thereby reduces photo quality to boot?! :)

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Extensions are long and unweildy - a TC provides a more compact package

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I use the Canon 100MM, if I know I am going for some really small stuff then I use my EF25II extention tube, it will let you focus to about 6-8 inches but only has a focus range of about 12, so anything past 12 inches you can't focus on.

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And if you can double the magnification with an extension tube, why would anyone use a 2X TC, which has a (significantly) higher price, and which introduces extra glass and thereby reduces photo quality to boot?!   :)

 

I'm not convinced that using the 2x results in un-acceptable photo quality. Frankly, my goal is to spend enough time with this set-up to show that the photos are up to snuff. It's just the right dive trip conditions need to present themsleves. One more with the 2xTC:

 

tiffDSC_2111clown1600-02.jpg

 

Rand

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Indeed there is light loss, you loose 1 stop when youre at 1:1, I remember that Canon use a cheater when displaying their F stop, it's described somewhere in the lens or camera manual, but with Nikon when your at 1:1 your display shows F:4 not F:2,8 at maximum aperture and minimum focusing. once you are at f:4 or smaller, the system maintain the f stop choosen, on the opposite side your smallest is f:45 at minimum but convert to f:32 at infinity focus. hope It make senses :)

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On the topic of teleconverter, they do induce a quality loss, but I suspect that since we use the center part of the lens and converter, the quality loss is not as dramatic as it used to be with full frame. I for one find these converter perform better now in digital than before in 35mm. In the end whatever work for you is best for you.

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The extension tubes will allows closer focusing resulting in higher magnification, this without loss of opticall quality but the drawback is proximity, you end up being much closer so use only with longer focal lenght.

 

 

I don't think you can make this assumption for evey lens. Even though an extension has no glass to distort the image, it places the lens further away from the image plane than it is designed for. The optical quality is not guaranteed.

 

I've used both TC and diopters with good results. Sometimes both at the same time. The shot below was taken with the Canon 100mm with a 1.4x TC and a +2 diopter. F/6.3 which is effictively F/9 for shallow DOF.

 

CRW_8168.jpg

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That's a killer shot Herb. With that setup on a 1.6x crop camera, you are talking about a very small field of view!

 

Cheers

James

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Good TCs should induce little degradation when used on macro lenses in artificial light and relatively small apertures. This is according to John Shaw's texts. Remember that TCs are designed for much more demanding situations - shooting distant subjects at wide apertures. Birders would envy the results we get shooting 2X or 3X TCs under water!

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Rand, killer shot on that Christmas tree worm, absolutely love it!

 

I am using a lot of close up filters myself these days, was going to use the 1.4TC but they sent me the wrong one....

 

I like the limited DOF it gives and i think is an easy way to go, without having to worry about extra length on your lenses and ports.

Too bad Chris Bangs doesn't seem to post on here these days, he has some great examples of using all sorts of combinations as that is one of his specialties (guess he is too busy taking photos of children!!!! :D:D:D )

 

However, i do find that the filters do work with a 60mm, this is an example of 60mm with a +4. True, i had to get right on them to get this full frame but..it worked...luckily they were turned this way

post-2598-1120793358_thumb.jpg

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In the good old days of manual focusing most macro lenses (e.g. 55/3.5, 105/4, and 200/4 Micro-Nikkors) only focused to 1:2 (half life size) so special extension tubes were sold to match to the focal lengths so as to yield 1:2 to 1:1 focusing range for some lenses. For example the Nikon PK-13 ring is 27.5mm long and was designed for the 55 whereas the PN-11 was for the 105. These two lenses also focused to 1:2 simply by racking out the lens elements, the extension tube carried this out for another increment equal to that intrinsic to the lens. When the 200 came out, it had internal focus (IF) and no extension tube came out for it. My recollection was the that the TC-300 teleconverter (TC; a.k.a. doubler) was recommended to bring the 200 to 1:1 but the PN-11 could be used too but less than 1:1 resulted. The IF enables lenses to compensate for lens aberrations induced by change in focus distance. This would be lost if an extension tube was used but would be conserved if a TC was used.

 

The bellows correction factor (due to loss of light by the extension) was engraved on the barrel of some MF macro lenses, two scales on some for use with and without the 1:1 tube. With the advent of TTL metering and TTL flash, the bellows correction factor was all but forgotten since the metering system took care of it. Interestingly, the 50 macro lens for the Nikonos RS has an automatic compensation so that as the lens is focused to 1:1, it opens up a tad. Therefore, f/22 remains T/22, (T-stop, not f/stop) but the DOF is that of the compensated aperture, i.e., less DOF. I criticized this 'feature' in my review of the RS that I did for the AAUS a decade or so ago. This is good for some folks, but DOF is sacrificed as a result.

 

The main problem of using an extension or TC UW is that one may have to use special lens gears; unless you have one of those ports that incorporates focusing and have a port extension tube that is the same length as your lens extension tube. Alternatively, you would have to do your dive at a fixed focus distance, like in the days of Nikonos (I to V) extension tubes and framers (remember them?).

 

BTW, I believe the EOS Canon 50 macro lens only goes to 1:2 and needs a tube to go to 1:1 like many MF focusing macros.

 

Tom

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ps. forgot to mention that there are formulas for calculating the bellows correction factor, DOF etc. but are not to practical for UW use, one needs to know the total extension (tube plus amount due to lens focusing) and focal length and use a calculator. I recall one even includes pupillary magnification. One would need more input data.

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However, i do find that the filters do work with a 60mm, this is an example of 60mm with a +4.  True, i had to get right on them to get this full frame but..it worked...luckily they were turned this way

 

 

I don't think that this shot demonstrates magnification beyond the native 60mm micro - unless those are pygmy mandarinfish :D

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Well, in order to get them to fill that much of the frame (its full frame, no crop) i needed to be right on top of em, regular 60mm won't get you that full of a frame without the diopter (might have been a +2 as opposed to a +4...) but definitely more than just the regular 60 could do, believe me i tried on many occasions. Then i bought the 105....:D much less frustrating that way, mandarins don't like it when you're port is only 3 inches away, ruins their sex drive...:D

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I like the limited DOF it gives and i think is an easy way to go, without having to worry about extra length on your lenses and ports.

Too bad Chris Bangs doesn't seem to post on here these days, he has some great examples of using all sorts of combinations as that is one of his specialties (guess he is too busy taking photos of children!!!! :D:D:D )

 

However, i do find that the filters do work with a 60mm, this is an example of 60mm with a +4. True, i had to get right on them to get this full frame but..it worked...luckily they were turned this way

 

Very Funny Manta breath!

 

sorry about the long hiatus. The peak kiddy shooting season is over, now I can get back to concentrating on UW stuff.

 

I found that using (+) filters on the 60mm reduced my working distance too much when shooting at max reproduction. I have used such filters with the 105 mm with decent results.

 

For the intense macro up to 10:1 teleconverters are required, In the future I plan to put the 200 mm micro lens to use. I will experiment with the (+) filters when using that lens

 

Chris

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