Does the Minolta MD 24-35/f3.5 lens have any aspherical or floating elements?

I'm in the process of creating a custom lens panel to mount one on my FrankenKamera VII for a project I have in mind and it sure will be convenient if the answer is No, because this will simplify the process quite a lot.

I've searched quite a bit trying to determine this one way or the other -- unfortunately, my guess is that it does -- but so far, I've been unable to find a definitive answer.

Any input will be gratefully appreciated ... thanks!

Neither. The MD 24-35 has a simple, classical, two-group design, without aspherical surfaces or floating elements.

AudiiDudii said:

1. AudiiDudii wrote:

I'm in the process of creating a custom lens panel to mount one on my FrankenKamera VII for a project I have in mind and it sure will be convenient if the answer is No, because this will simplify the process quite a lot.

I've searched quite a bit trying to determine this one way or the other -- unfortunately, my guess is that it does -- but so far, I've been unable to find a definitive answer.

Any input will be gratefully appreciated ... thanks!

Click to expand...

I don’t know but have a look at the following links

https://lens.ws/minolta-md-24-35mm-f3-5-zoom/

http://minolta.eazypix.de/lenses/index.html

http://allphotolenses.com/lenses/item/c_2673.html

These suggest a 10/10 design as you might expect for a WA fixed aperture zoom ( well moderate WA in today’s terms.

No aspherical.

They say ““yes” to floating elements but that could be their definition of that term . Sure minolta people here will be able to give you a definitive answer. No CRC floating group eg like there is on some WA ais Nikkors

Looks like a really nice lens for its era..

Volker G said:

Neither. The MD 24-35 has a simple, classical, two-group design, without aspherical surfaces or floating elements.

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Can you point me to a reference that supports this? No offense intended, just curiosity...

rich_cx139 said:

AudiiDudii said:

I'm in the process of creating a custom lens panel to mount one on my FrankenKamera VII for a project I have in mind and it sure will be convenient if the answer is No, because this will simplify the process quite a lot.

I've searched quite a bit trying to determine this one way or the other -- unfortunately, my guess is that it does -- but so far, I've been unable to find a definitive answer.

Any input will be gratefully appreciated ... thanks!

Click to expand...

I don’t know but have a look at the following links

https://lens.ws/minolta-md-24-35mm-f3-5-zoom/

http://minolta.eazypix.de/lenses/index.html

http://allphotolenses.com/lenses/item/c_2673.html

These suggest a 10/10 design as you might expect for a WA fixed aperture zoom ( well moderate WA in today’s terms.

They say ““yes” to floating elements but that could be their definition of that term . Sure minolta people here will be able to give you a definitive answer.

Click to expand...

I've already seen all those links, but thanks...

Member said:

Looks like a really nice lens for its era..

Click to expand...

I've only had it for a few days and taken only a handful of test photos with it to confirm it's performing well enough to keep, but I can say it renders quite differently than the C/Y and CN lenses that I typically use. For example:



That said, I find its softer, less contrasty, less saturated rendering style appealing in many ways, hence I am now thinking about using it for projects other than the one I specifically had in mind when I bought it.

rich_cx139 said:

Member said:

1. AudiiDudii wrote:

I'm in the process of creating a custom lens panel to mount one on my FrankenKamera VII for a project I have in mind and it sure will be convenient if the answer is No, because this will simplify the process quite a lot.

I've searched quite a bit trying to determine this one way or the other -- unfortunately, my guess is that it does -- but so far, I've been unable to find a definitive answer.

Any input will be gratefully appreciated ... thanks!

Click to expand...

I don’t know but have a look at the following links

https://lens.ws/minolta-md-24-35mm-f3-5-zoom/

http://minolta.eazypix.de/lenses/index.html

http://allphotolenses.com/lenses/item/c_2673.html

These suggest a 10/10 design as you might expect for a WA fixed aperture zoom ( well moderate WA in today’s terms.

No aspherical.

They say ““yes” to floating elements but that could be their definition of that term . Sure minolta people here will be able to give you a definitive answer. No CRC floating group eg like there is on some WA ais Nikkors

Looks like a really nice lens for its era..

Click to expand...

With a two-group design, the lens designers designate a configuration with two main groups which are increasing the distance relative to each other when moving the zoom ring. It was invented by Canon (1976, FD 35-70 mm f/2.8-3.5 SSC) and first used by Nikon in a wide-angle zoom lens (Nikkor 28-45 mm f/4.5). So nothing to do with the number of independent lens elements....

The MD 24-35 mm is definitely a nice and very compact lens that hardly gets bigger or heavier than a fixed focal 24, 28, or 35 mm lens. I've got one (as well as one sample of the MD 24-50 mm f/4), but I don't use it often since it just doesn't deliver sharp corners on full-frame sensor cameras without closing the aperture to f/11.

I had thought that floating elements -well the sort that improve aberration control in close focus were confined to primes like the many that minolta did ( think they invented that system? ).

EDIT : from Volker G's post I was obviously wrong - didn't know about the Canon and Nikon zooms.

FWIW: Also use C//Y mostly - not had any problems with critical reg distance due to short adapters cf novoflex on zooms but that would be 35-75/3.4 and a 80-200/4. Think I read it’s worse with WA.

On the other hand, I have had no probs either with my ais 24 and 28 CRC’s on many extremely dubious cheap and short adapters on a multitude of bodies. Maybe it just me not knowing where to look.

Volker G said:

The MD 24-35 mm is definitely a nice and very compact lens that hardly gets bigger or heavier than a fixed focal 24, 28, or 35 mm lens. I've got one (as well as one sample of the MD 24-50 mm f/4), but I don't use it often since it just doesn't deliver sharp corners on full-frame sensor cameras without closing the aperture to f/11.

Click to expand...

As my sample photo shows, I'll be cropping the photos to a 16:10 format, which helps the soft corners very slightly by cropping the furthest parts.

I also photograph almost exclusively at night, so the corners are usually hidden in either a black sky or dark shadows.

Unfortunately, I also want to use the lens with rise / fall movements and as best I can tell at this point, it projects a fairly small image circle across its range.

But as you note, it's compact and lightweight, which is an important factor as well, so who knows how it will ultimately work for my purposes?

Thanks for the input!

rich_cx139 said:

I had thought that floating elements -well the sort that improve aberration control in close focus were confined to primes like the many that minolta did ( think they invented that system? ). Can’t find a reference to that.

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I don't know of any reason why floating elements cannot be used with a zoom lens, but it definitely would complicate the mechanical aspects of its design to do so.

Member said:

Also use C//Y mostly - not had any problems with critical reg distance due to short adapters cf novoflex on zooms but that would be 35-75/3.4 and a 80-200/4. Think I read it’s worse with WA.

Click to expand...

I haven't had any issues with my C/Y lenses, either, but I was also able to set the FFD of my DIY shift lens adapter just about perfectly, so I wouldn't expect any issues either way.

This is actually the issue that's involved here, because due to thickness of the carbon fiber sheet from which I'll be making the lens panel and the lens mount bayonet I'll be using, I'll have to add a fairly thick shim, which complicates matters quite a bit. If the lens does not have any floating or aspherical elements, the requirement to precisely achieve the correct FFD is relaxed a bit and in turn, this makes fabricating a lens panel a little bit easier.

rich_cx139 said:

AudiiDudii said:

I'm in the process of creating a custom lens panel to mount one on my FrankenKamera VII for a project I have in mind and it sure will be convenient if the answer is No, because this will simplify the process quite a lot.

I've searched quite a bit trying to determine this one way or the other -- unfortunately, my guess is that it does -- but so far, I've been unable to find a definitive answer.

Any input will be gratefully appreciated ... thanks!

Click to expand...

I don’t know but have a look at the following links

https://lens.ws/minolta-md-24-35mm-f3-5-zoom/

http://minolta.eazypix.de/lenses/index.html

http://allphotolenses.com/lenses/item/c_2673.html

These suggest a 10/10 design as you might expect for a WA fixed aperture zoom ( well moderate WA in today’s terms.

They say ““yes” to floating elements but that could be their definition of that term . Sure minolta people here will be able to give you a definitive answer.

Looks like a really nice lens for its era..

Click to expand...

In my simple understanding of the term "floating element" any focusing mechanism that will move two or more groups / elements independently has floating elements. Including going the same direction but at different rates, at different directions or one element or group of them not moving at all. If for focusing in a zoom only the shifting of one element or group is used (not uncommon) and other movements are only used for the zoom function then in my opinion it still falls within the floating element category. IMHO.

I guess the OP is concerned about getting the lens panel exactly placed at the original register distance for that lens as any other distance will not be optimal and there is no easy/good fix in calibrating the lens internally to infinity. Primes without floating elements would allow the last without a penalty.

With my 3D printed EF bayonet sleeve for the Minolta MD III 35-70mm 3.5 the original MD flange rests on the flange of the EF female bayonet part but at 0,5mm further than the 43,5mm register distance of the MD mount. I could adjust it at the front focusing group of that lens. However not optimal. At a later stage I corrected that by checking the lens mount assembly and removing a 0,5mm shim of the three shims there. Followed by a new infinity calibration.


Met vriendelijke groet, Ernst
No photographer's gear list is complete without the printer mentioned !

OK thanks for the explanation Volker G.

E Dinkla said:

I guess the OP is concerned about getting the lens panel exactly placed at the original register distance for that lens as any other distance will not be optimal and there is no easy/good fix in calibrating the lens internally to infinity. Primes without floating elements would allow the last without a penalty.

Click to expand...

You are correct and this is exactly the issue I'm trying to address. Given that my lens panel will take some time to fabricate, mostly by hand, the degree to which I have to achieve the exact FFD will dictate which of the two lens bayonets I have available I decide to use.

If I choose the wrong one, I'll have to fabricate a new lens panel from scratch, which I'd like to avoid, if possible.

rich_cx139 said:

I had thought that floating elements -well the sort that improve aberration control in close focus were confined to primes like the many that minolta did ( think they invented that system? ).

Click to expand...

In fact, there are several zoom lenses using floating elements. Among the wide-angle zooms I have, the Sigma 21-35 mm f/3.5-4.2 and the Canon FD 20-35 mm f/3.5 use them to improve field flatness throughout the focusing range - while both lenses have a two-group design (see above), some lenses of the first group move relative to the others when you turn the focusing ring.

If it had floating elements I'm sure it would have had a shorter MFD and not require a shift into the "macro" mode, which was an innovation that was coming soon to a zoom near you...
I'm not sure who did it first in a zoom.
Google says:
Why I love the internet: https://eyesofageneration.com/reel-history-cinemas-first-known-zoom-lens-shot-it-1927in-this-clip-s/

https://www.zoomlenshistory.org.uk

A nice little bonus, a zoom patent 1st April 1902: https://zoomlenshistory.org.uk/wp-content/uploads/2011/08/clile-allen-patent-686788.jpg

AudiiDudii said:

http://forum.mflenses.com/who-made-the-first-floating-element-design-t47591.html#1212674
The first floating element used in a lens happened, simply, with the first zoom lens released ;-)

Click to expand...

I'm not sure if this was sarcasm... IMO it's more complicated than that.

Zooms generally fall into 4 types, the first 2 were more common pre 80's:
Varfocal https://en.m.wikipedia.org/wiki/Varifocal_lens

AudiiDudii said:

A varifocal lens is a camera lens with variable focal length in which focus changes as focal length (and magnification) changes

Click to expand...

There is technically a floating element when zooming a verifocal zoom, but when you are only focusing, it's unit focus.
So IMO it's not a floating design. Vivitar S1 28-105mm
https://www.premiumbeat.com/blog/how-to-use-zoom-lenses/



Parfocal https://en.m.wikipedia.org/wiki/Parfocal_lens

AudiiDudii said:

A parfocal lens is a lens that stays in focus when magnification/focal length is changed. There is inevitably some amount of focus error, but too small to be considered significant.

Zoom lenses used for moviemaking applications must have the parfocal ability in order to be of practical use. It is almost impossible to stay in correct focus (as done manually by the focus puller) while zooming.

Click to expand...

https://www.studiobinder.com/blog/what-is-a-parfocal-lens-definition/

AudiiDudii said:

With these lenses, on the other hand, the focus mechanism and zoom mechanism move independently from each other.

Click to expand...

https://www.studiobinder.com/blog/what-is-a-parfocal-lens-definition/

https://s.studiobinder.com/wp-content/uploads/2021/05/Parfocal-camera-lens-vs-Varifocal-lenses.jpg



I'm not sure how to judge this one, I don't have one in my collection to see how the elements behave during focusing, nor are all designs the same, so IMO, most parfocal lenses are likely a floating design, at the very least it's closer to a "floating" system than a verifocal lens is.

A nice demo: https://www.diyphotography.net/know-parfocal-varifocal-lenses/

Post 70's you start to see zooms with internal focus, they're a different beast, that I do consider to be floating design since they are not unit focusing. Canon EF 35-105

Afocal https://en.m.wikipedia.org/wiki/Afocal_system

AudiiDudii said:

In optics an afocal system (a system without focus) is an optical system that produces no net convergence or divergence of the beam, i.e. has an infinite effective focal length.[1] This type of system can be created with a pair of optical elements where the distance between the elements is equal to the sum of each element's focal length

Click to expand...

I don't have many zooms to confirm my thoughts, so salt to taste.

--
A Manual Focus Junky...
One photographers junk lens is an artists favorite tool.
http://www.flickr.com/photos/lightshow-photography/
[My Lens list](http://www.fredmiranda.com/forum/viewprofile.php?Action=viewprofile&username=LightShow)
####Where's my FF NEX-7 ?????
Firmware request:
-A button map for toggling the EVF & LCD
-Still waiting for the minimum shutter speed with auto ISO for my NEX-7 and A7r. I know it will never happen.
-Customize the display screen layout, I'd love to have both Histogram and level at the same time.
-More peaking options, being able to set peaking sensitivity and a threshold level.
-An RGB overlay on the histogram -An option to return the focus assist zoom to one button press
-An option to return to how the NEX-7 handled playback, ie. center button to zoom, then you could use the control dial to zoom in and out, then center button to exit the zoom mode.

Lightshow said:

If it had floating elements I'm sure it would have had a shorter MFD and not require a shift into the "macro" mode, which was an innovation that was coming soon to a zoom near you...

Click to expand...

That's hardly an argument since the MD 24-35 mm doesn't have a "macro mode" with switch but a direct access 0,3 m MFD ;-)

Furthermore, IF mainly helps with "longer" focal length lenses, the MFD of the aforementioned Sigma 21-35 and Canon FD 20-35 L (0,5 m) prove my point.

Volker G said:

Lightshow said:

If it had floating elements I'm sure it would have had a shorter MFD and not require a shift into the "macro" mode, which was an innovation that was coming soon to a zoom near you...

Click to expand...

That's hardly an argument since the MD 24-35 mm doesn't have a "macro mode" with switch but a direct access 0,3 m MFD ;-)

Click to expand...

I don't know why but I was thinking of the 35-70 when I wrote that.

Volker G said:

Furthermore, IF mainly helps with "longer" focal length lenses, the MFD of the aforementioned Sigma 21-35 and Canon FD 20-35 L (0,5 m) prove my point.

Click to expand...

The remainder of my post was zooms in general.

--
A Manual Focus Junky...
One photographers junk lens is an artists favorite tool.
http://www.flickr.com/photos/lightshow-photography/
[My Lens list](http://www.fredmiranda.com/forum/viewprofile.php?Action=viewprofile&username=LightShow)
####Where's my FF NEX-7 ?????
Firmware request:
-A button map for toggling the EVF & LCD
-Still waiting for the minimum shutter speed with auto ISO for my NEX-7 and A7r. I know it will never happen.
-Customize the display screen layout, I'd love to have both Histogram and level at the same time.
-More peaking options, being able to set peaking sensitivity and a threshold level.
-An RGB overlay on the histogram -An option to return the focus assist zoom to one button press
-An option to return to how the NEX-7 handled playback, ie. center button to zoom, then you could use the control dial to zoom in and out, then center button to exit the zoom mode.

IF lenses most often get part of their focusing done by a focal length change which is basically a zoom function with floating element(s). Simple examples are found in the front cell focusing of Triplets and Tessars.

Met vriendelijke groet, Ernst
No photographer's gear list is complete without the printer mentioned !

A practical test is to put it on a too short adapter and redo the same test on one that is perfect in length. If the corners are better on the correct length one, it might well have floating element.

lattesweden said:

A practical test is to put it on a too short adapter and redo the same test on one that is perfect in length. If the corners are better on the correct length one, it might well have floating element.

Click to expand...

I was trying to avoid doing this because I'm the one who is making the adapters and I would rather make just one than two.

And while I didn't receive a definitive answer to my question, I do think I have come up with a workable solution to the underlying issue that caused me to raise it.

My thanks to everyone who responded, as I learned a few things from your comments! 8^)