Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

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Lou Jost
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by Lou Jost »

Lou, I agree with everything you say apart from your wording about extension tubes providing magnification at the price of working distance.
Dick, I think my wording is accurate, at least when comparing teleconverters versus extension. If you focus a lens on an object, and add a 2x teleconverter. the lens will not need to be refocused. You will have doubled the magnification but there will be no loss of working distance. Now instead of adding a teleconverter, you add extension tubes to double the magnification. Now the lens needs to be refocused, and the direction of refocusing has to be the direction that moves the aerial image backwards towards the sensor. In other words, you have to focus closer. So you lose working distance relative to the teleconverter solution. And the difference can be very large. That's what I was trying to say in the post.
Floating element focussing and close up lenses extension tubes give you magnification at the expense of working distance.
I think you may be using the term "floating elements" differently than me. Floating elements don't necessarily alter the point of focus, or the focal length. They are any elements that move within the fixed lens assembly when the lens is refocused, usually to maintain lens corrections. For example, some Mamiya RZ67 lenses have floating elements that move (manually) to maintain corner quality as the lens is refocused. Early Nikon lenses had floating elements for the same reason. They do not necessarily change working distance. They might, though. The main point is that lenses with mechanically controlled floating elements will have worse optical quality when used with extension than when used with a teleconverter, because the elements won't be set to their correct positions for that focal point.
Extension tubes give you magnification at the expense of some loss of image quality and some working distance, but a lot less than floating elements or diopters.
As I understand the term, floating elements INCREASE image quality.
You therefore gain working distance when instead of a close up lens you use an extension ring.
This isn't clear to me, so I have no opinion about this.
If working distance is the highest priority, you may gain working distance by focussing the lens to infinity and use extension rings to focus closer. Not ideal optically of course.
I don't see this, at least when compared to teleconverters. The teleconverter always wins over extension tubes for working distance.
Have you ever tested whether using a 1.4x teleconverter gives you more useful resolution than cropping in your system?
This should depend mainly on the resolution of the prime lens. I have seen tests showing that it does give additional resolution if you stay under the diffraction limit. Also, theoretically, if you upscale the original image by a factor of two, you will have very coarse color resolution relative to the image obtained from a 2x teleconverter. Each block of four pixels in the upscaled image is based on only one actual color measurement, while the corresponding block of four image pixels on the teleconverter image will be based on R, G, G, and B measurements.

You could ask the same thing about extension versus cropping and upscaling. For a given lens, I should think the answer will be about the same whether you use a teleconverter or extension tubes. as long as the teleconverter is a good one.
Interesting. Is yours the Apo Xenoplan 35/1.8 or the Apo Xenoplan 35/2.0?
It's the f/1.8. Lovely lens.

dolmadis
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by dolmadis »

Lou Jost wrote:
Fri Dec 16, 2022 1:29 pm
dolmadis wrote:
Thu Dec 15, 2022 12:30 am

Hi Lou

Could I ask please which reversed lenses you use give you the best results with the zoom you referred to earlier?

Thanks, John
John,
Sure, here is what worked well for me, organized by field of view, from 5x to 1x. Step sizes for auto-bracketing refer to Oly PEN-F cameras; Panasonic G9 step sizes should be about 2x the Oly sizes:

3.4-5mm Apo Xenoplan 35 f/2.8 or a bit higher, step size 4
4-5mm Mitu 2.5x QV Step size 2, maybe larger.
5-7mm Oly Four-Thirds 50mm macro f/4 ½ or perhaps higher, step size 1, maybe 2.
6-8mm Apo Comp 60 f/4 ½, step size 3?.
9-11mm Oly Zuiko 90 f/2 @ f/4-8, step size 2-3
11- 17mm Raynox 250, forward mounted. Low m step size 2, high m step size 3. Useful also down to about 6mm.

By 4x or 5x the stacking depth was very limited.
Thanks Lou for finding the needles in that particular haystack. Best, John

dickb
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by dickb »

Lou Jost wrote:
Fri Dec 16, 2022 7:16 pm
Lou, I agree with everything you say apart from your wording about extension tubes providing magnification at the price of working distance.
Dick, I think my wording is accurate, at least when comparing teleconverters versus extension. If you focus a lens on an object, and add a 2x teleconverter. the lens will not need to be refocused. You will have doubled the magnification but there will be no loss of working distance. Now instead of adding a teleconverter, you add extension tubes to double the magnification. Now the lens needs to be refocused, and the direction of refocusing has to be the direction that moves the aerial image backwards towards the sensor. In other words, you have to focus closer. So you lose working distance relative to the teleconverter solution. And the difference can be very large. That's what I was trying to say in the post.
Lou, you are not wrong in saying that. But in my opinion in the original posts you are overemphasising the loss of working distance when using extension rings when you also mention the use of close up lenses. All I want to say in this thread is that extension rings can be a good solution if you value working distance over optimal IQ and teleconverters are not a viable option for your system.
Floating element focussing and close up lenses extension tubes give you magnification at the expense of working distance.
I think you may be using the term "floating elements" differently than me. Floating elements don't necessarily alter the point of focus, or the focal length. They are any elements that move within the fixed lens assembly when the lens is refocused, usually to maintain lens corrections. For example, some Mamiya RZ67 lenses have floating elements that move (manually) to maintain corner quality as the lens is refocused. Early Nikon lenses had floating elements for the same reason. They do not necessarily change working distance. They might, though. The main point is that lenses with mechanically controlled floating elements will have worse optical quality when used with extension than when used with a teleconverter, because the elements won't be set to their correct positions for that focal point.

You are right, I am mistakenly using the term floating elements here only for the way they are used in lenses when their goal is to improve close focus IQ and reduce lens size by reducing the focal length, as is the case for the 60mm Olympus.
Extension tubes give you magnification at the expense of some loss of image quality and some working distance, but a lot less than floating elements or diopters.
As I understand the term, floating elements INCREASE image quality.
Indeed, I meant the "but a lot less than floating elements or diopters" to only refer to the working distance, not the IQ. But I see that that may not be clear.
You therefore gain working distance when instead of a close up lens you use an extension ring.
This isn't clear to me, so I have no opinion about this.
I'm just saying the same thing again, at the same magnification extension rings give you more working distance than close up lenses.
If working distance is the highest priority, you may gain working distance by focussing the lens to infinity and use extension rings to focus closer. Not ideal optically of course.
I don't see this, at least when compared to teleconverters. The teleconverter always wins over extension tubes for working distance.
This is not true for the 60mm Olympus, not always. When focussed at 1:1, the true focal length is 37.54mm. Use a 1.4x teleconverter and you get 52.55mm. Still less than the 61mm the lens is at infinity, and remains with however many extension rings you need to get the same magnification. The image quality is likely to be clearly worse than the teleconverter setup, but the working distance will be greater.
Have you ever tested whether using a 1.4x teleconverter gives you more useful resolution than cropping in your system?
This should depend mainly on the resolution of the prime lens. I have seen tests showing that it does give additional resolution if you stay under the diffraction limit. Also, theoretically, if you upscale the original image by a factor of two, you will have very coarse color resolution relative to the image obtained from a 2x teleconverter. Each block of four pixels in the upscaled image is based on only one actual color measurement, while the corresponding block of four image pixels on the teleconverter image will be based on R, G, G, and B measurements.

You could ask the same thing about extension versus cropping and upscaling. For a given lens, I should think the answer will be about the same whether you use a teleconverter or extension tubes. as long as the teleconverter is a good one.
That is my guess as well.
Interesting. Is yours the Apo Xenoplan 35/1.8 or the Apo Xenoplan 35/2.0?
It's the f/1.8. Lovely lens.
Indeed it is. In fact they both are, but the 1.8 is better at higher magnifications, the 2.0 is better at lower magnifications, as it has a much larger image circle when not reversed.

Lou Jost
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by Lou Jost »

Thanks for the clarifications Dick. I think we both agree.
This is not true for the 60mm Olympus, not always. When focussed at 1:1, the true focal length is 37.54mm. Use a 1.4x teleconverter and you get 52.55mm. Still less than the 61mm the lens is at infinity, and remains with however many extension rings you need to get the same magnification. The image quality is likely to be clearly worse than the teleconverter setup, but the working distance will be greater.
That's a good point, you could force the lens to work at infinity by using extension tubes, at the cost of image quality, and this would give you the working distance appropriate to a 60mm lens when you move the camera + lens + tubes to get the system into focus. But these are complex asymmetrical lenses, and I am not sure if that really translates to better working distance (from the front of the lens to the subject) than for the equivalent teleconverter solution. It would be interesting to test. Have you done the experiment?

dickb
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by dickb »

Lou Jost wrote:
Sat Dec 17, 2022 7:35 am
Thanks for the clarifications Dick. I think we both agree.
I think so as well.
This is not true for the 60mm Olympus, not always. When focussed at 1:1, the true focal length is 37.54mm. Use a 1.4x teleconverter and you get 52.55mm. Still less than the 61mm the lens is at infinity, and remains with however many extension rings you need to get the same magnification. The image quality is likely to be clearly worse than the teleconverter setup, but the working distance will be greater.
That's a good point, you could force the lens to work at infinity by using extension tubes, at the cost of image quality, and this would give you the working distance appropriate to a 60mm lens when you move the camera + lens + tubes to get the system into focus. But these are complex asymmetrical lenses, and I am not sure if that really translates to better working distance (from the front of the lens to the subject) than for the equivalent teleconverter solution. It would be interesting to test. Have you done the experiment?
Interesting question - the focus distance in this extreme case will be longer with the extension tubes. But the total physical length of the lens plus tubes will be longer than that of the lens plus teleconverter, reducing the working distance. I don't know which option results in a longer working distance.

I don't think I own any macro lenses that have such a large reduction in focal length when focussed close as the 60mm Olympus. Most lenses in my collection are old fashioned extension based designs. My Sigma 150/2.8 is likely to be a floating elements design, but a 150mm lens needs a lot more extension than a 60mm, so in that case the 1.4x extender is sure to win the working distance contest.

Which brings me to the next question - does the AF in-camera-stacking on micro 4/3 cameras only work with Olympus and Panasonic lenses or is it possible with older adapted lenses like the Sigma 150mm in EF or 4/3 mount? That would be an interesting way to get more working distance than any 60 or 90mm lens.

Lou Jost
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by Lou Jost »

No Dick, it only works with modern MFT lenses. I am not sure if it would even work on off-brand MFT lenses like Sigma. I expect not. At the very least, the camera has to calculate the appropriate unit step size, which requires information from the lens.

CarlosHermosilla
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by CarlosHermosilla »

In the interesting discussion that's been going on, I'm wondering how to fit a 1.4x doubler on the Olympus 60mm macro because the M4/3 teleconverters have the rear lens housed in a long tube that prevents these teleconverters from being placed on lenses that aren't They are specifically made for this use. On this subject I made a modification of an extension tube that allows to place a teleconverter in the Olympus 60mm macro:
https://flic.kr/p/2kTLu6H https://flic.kr/p/2kTJ4SR https://flic.kr/p/2kTJ4Vm

Thanks

Carlos

enricosavazzi
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by enricosavazzi »

dickb wrote:
Sat Dec 17, 2022 1:04 pm
[...]
Which brings me to the next question - does the AF in-camera-stacking on micro 4/3 cameras only work with Olympus and Panasonic lenses or is it possible with older adapted lenses like the Sigma 150mm in EF or 4/3 mount? That would be an interesting way to get more working distance than any 60 or 90mm lens.
As far as I know, Olympus cameras only do in-camera focus stacking with a subset (maybe about half or one-third) of the current Olympus Micro 4/3 lenses. Olympus publishes a list of which of their lenses work with this feature, and the list grows as new lenses are released, so you need to update the camera's firmware to be able to use this and other features with new lenses. I have no idea whether Olympus cameras do in-camera focus stacking with any of the Panasonic Micro 4/3 lenses.

I am pretty sure that in-camera focus stacking does not work with any of the legacy 4/3 lenses. It is also not supported with any adapted third-party lenses originally equipped with mounts other than Micro 4/3.

I have read/heard of hacked versions of Olympus firmware that allow in-camera focus stacking also with some (I don't know which, how many, and how well it works) lenses not officially supported by Olympus. I have no intention of trying any of these hacked firmware versions on my cameras.
--ES

enricosavazzi
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by enricosavazzi »

CarlosHermosilla wrote:
Sat Apr 22, 2023 6:21 am
In the interesting discussion that's been going on, I'm wondering how to fit a 1.4x doubler on the Olympus 60mm macro because the M4/3 teleconverters have the rear lens housed in a long tube that prevents these teleconverters from being placed on lenses that aren't They are specifically made for this use. On this subject I made a modification of an extension tube that allows to place a teleconverter in the Olympus 60mm macro:
https://flic.kr/p/2kTLu6H https://flic.kr/p/2kTJ4SR https://flic.kr/p/2kTJ4Vm

Thanks

Carlos
I know that extension tubes work on Micro 4/3 because they only contain straight wires between their rear and front electrical contacts. I also know that Olympus teleconverters are "dumb" devices without internal electronics, so a stack of extension tubes and one teleconverter should work transparently, just like a stack of extension tubes.

The camera simply has no way to know that extension tubes are being used.

When a lens that supports teleconverters is attached at the front of a teleconverter, the lens reads the presence of the teleconverter by using one of the two extra electrical pins at the front of the teleconverter and at the rear of the lens. The lens then tells the camera that a teleconverter (and which teleconverter, 1.4x or 2x) is attached, and the camera factors this into the displayed focal length and lens aperture. The camera also does the necessary adjustments to IS and other functions. The camera, however, has no way to directly detect a teleconverter. The lens must tell this to the camera.

Lenses that do not support a teleconverter have no way to detect whether a teleconverter is attached at the rear of the lens, either directly or via extension tubes.

As far as I know, no Micro 4/3 extension tubes have the extra pins used by teleconverters.
--ES

CarlosHermosilla
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by CarlosHermosilla »

Yes. But Panasonic's 1.4 x teleconverter can't be put on the Olympus 90mm macro because it doesn't fit. Teleconverters are very special, dedicated to only a small list of lenses. Today with the setup I have pointed out I have been able to use the Panasonic 1.4 x teleconverter with the Olympus 90mm macro lens since I have not bought the Olympus 1.4 x yet. All the best.

CarlosHermosilla
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Re: Best Lens/Accessory Option to Achieve 1.5-2:1 Magnification with Micro Four Thirds?

Post by CarlosHermosilla »

dickb wrote:
Sat Dec 17, 2022 1:04 pm
Lou Jost wrote:
Sat Dec 17, 2022 7:35 am
Thanks for the clarifications Dick. I think we both agree.
I think so as well.
This is not true for the 60mm Olympus, not always. When focussed at 1:1, the true focal length is 37.54mm. Use a 1.4x teleconverter and you get 52.55mm. Still less than the 61mm the lens is at infinity, and remains with however many extension rings you need to get the same magnification. The image quality is likely to be clearly worse than the teleconverter setup, but the working distance will be greater.
That's a good point, you could force the lens to work at infinity by using extension tubes, at the cost of image quality, and this would give you the working distance appropriate to a 60mm lens when you move the camera + lens + tubes to get the system into focus. But these are complex asymmetrical lenses, and I am not sure if that really translates to better working distance (from the front of the lens to the subject) than for the equivalent teleconverter solution. It would be interesting to test. Have you done the experiment?
Interesting question - the focus distance in this extreme case will be longer with the extension tubes. But the total physical length of the lens plus tubes will be longer than that of the lens plus teleconverter, reducing the working distance. I don't know which option results in a longer working distance.

I don't think I own any macro lenses that have such a large reduction in focal length when focussed close as the 60mm Olympus. Most lenses in my collection are old fashioned extension based designs. My Sigma 150/2.8 is likely to be a floating elements design, but a 150mm lens needs a lot more extension than a 60mm, so in that case the 1.4x extender is sure to win the working distance contest.

Which brings me to the next question - does the AF in-camera-stacking on micro 4/3 cameras only work with Olympus and Panasonic lenses or is it possible with older adapted lenses like the Sigma 150mm in EF or 4/3 mount? That would be an interesting way to get more working distance than any 60 or 90mm lens.

I have tried with a Viltrox NF-M1 adapter that allows to focus Nikon lenses (with internal focus motor) on M4/3 cameras, these lenses then autofocus but the focus bracketing does not work, unfortunately.

Thanks

Carlos

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