Do Sony E lens apertures stay open when lens is off cam?

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Lou Jost
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Do Sony E lens apertures stay open when lens is off cam?

Post by Lou Jost »

I am thinking about buying a Sony E mount lens to use reversed on my other lenses. This would only work if the aperture stays open when the lens is off the camera. Can a Sony user tell me if that is how the E-mount lenses behave?

Thanks in advance!

HansH
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Post by HansH »

I checked some Sony lenses for E-mount.
After switching-off the camera the aperture closes to about f:16.

The aperture stays open when taking the lens off the camera whilst under power.
Not sure if that damages lens or camera.


Greetings Hans.

Lou Jost
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Post by Lou Jost »

Thank you Hans. So I need to buy a Sony E-mount camera along with the lens, to keep it open. That complicates things....

The lens in question is the Apo-Lanthar 65mm f/2.0. That's an attractive aperture for a reversed lens, and I expect it will be nearly apochromatic and well-corrected even at f/2.0.

Edit-- I can rent a Sony camera to open it, and it should stay permanently open, I assume.

Lou Jost
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Post by Lou Jost »

Looks lik ethe Apo-Lanthar 65mm has a manual aperture ring, so maybe there is no problem.

austrokiwi1
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Post by austrokiwi1 »

I dimly recall reading somewhere that removing an AF e-mount lens while the camera is turned on could cause damage. I am not sure how that could occur... assuming my memory is correct.

Is really worth spending Euro999.00 just to reverse the lens? The new lanthar is manual focus and you could use it the way you propose... but I am sure some of the other lenses you have would do just as well, perhaps even better.
Last edited by austrokiwi1 on Fri Aug 04, 2017 11:45 am, edited 1 time in total.
Still learning,
Cameras' Sony A7rII, OLympus OMD-EM10II
Macro lenses: Printing nikkor 105mm, Sony FE 90mm F2.8 Macro G, Schneider Kreuznach Makro Iris 50mm , 2.8, Schnieder Kreuznach APO Componon HM 40mm F2.8 , Mamiya 645 120mm F4 Macro ( used with mirex tilt shift adapter), Olympus 135mm 4.5 bellows lens, Oly 80mm bellows lens, Olympus 60mm F2.8

HansH
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Post by HansH »

I just tried a Sigma e-mount lens. Adjusted to fully open, took it off under power, aperture did not change. The same with (arbitrary) value f:4. The aperture is probably controlled by a stepper motor.

It seems that Canon lenses operate the same way.

I am very curious to the results with the Voigtländer lens.


Greetings Hans.

HansH
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Post by HansH »

From the Voigtländer instruction manual:

"Voigtländer E-mount lenses are designed for use on E-mount camera body. The lenses cover the full frame format. They are manually controlled lenses so the user sets focus and aperture ...."

Greetings Hans.

Lou Jost
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Post by Lou Jost »

Hans, I read that, but it still could be that the aperture does something unexpected when taken off power....I have learned to try not to take things for granted with lenses.

For example, on my last trip to the US I bought a Nikon-mount Sigma 135mm Art lens, supposedly one of the sharpest consumer lenses ever tested. I had the 50mm Art lens and expected the 135 to have a similar aperture control mechanism (no aperture ring but with Nikon's mechanical lever). But no, they removed the mechanical lever, so I can't stop it down when I use it on my MFT cameras. Bad mistake.

Macrero
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Post by Macrero »

austrokiwi1 wrote:Is really worth spending Euro999.00 just to reverse the lens? The new lanthar is manual focus and you could use it the way you propose... but I am sure some of the other lenses you have would do just as well, perhaps even better.
My thoughts as well. Too much money and complication for most likely a not really very stunning result. I don't think it's worth it, but hey, it's your money...
https://500px.com/macrero - Amateurs worry about equipment, Pros worry about money, Masters worry about Light

Lou Jost
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Post by Lou Jost »

Austrokiwi, Macrero, if I want to fully utilize my MFT sensor at 50-80Mp, the lens must have an effective aperture wider than f8. That's hard when m>2.0. If the reversed lens achieves m=2 by extension, it would have to be very sharp (close to diffraction-limited) at about f/2.6. If it achieves m=3 by extension, it would need to be very sharp at f/2.0.

I get an improvement if I use coupled lenses. In that case, to get m=2 I need a reversed lens that is very sharp at f/4.0. To get m=3 the lens needs to be very sharp at f/2.6. Most good lenses need to be stopped down at least two stops before they are very sharp (diffraction-limited). So if I subtract 2 stops from each of those numbers, I find that I need to start with an f/1.4 or f/2.0 lens.

I've been playing with such lenses and getting marvelous resolution with the best ones, but always with some unwanted purple fringing and sometimes with traces of LoCA also. If I could find a lens that was more nearly apochromatic and that had a maximum aperture of f/2.0 or wider and that was diffraction-limited when stopped down a couple of stops, I'd be in good shape.

There are very few such lenses. The Sigma 50mm Art lens is excellent but my copy (which had been dropped by an airline employee so may not be a good copy) shows quite a lot of LoCA. There's an Olympus f/2.0 macro which is great but has purple fringing. Still playing with that to see if I can stop it down far enough to rid myself of purple fringes but still leave it wide enough to escape diffraction. There's also an Olympus film-era 90mm f/2.0 macro which gives very good results, but not perfect. The Sigma 135mm f/1.8 is also very good but not perfect. The Apo-Lanthar f/2.0 seems worth checking if it controls color aberrations better than the above-mentioned lenses.

Also, I am so enamored by mirrorless cameras that I suspect one day I will buy a FF Sony mirrorless. Just waiting for the next upgrade. Before I pull the trigger I would like to see flash compatibility in electronic-shutter mode (as in my Olympus) and no downgrade to lower-bit file depths when shooting the electronic shutter.

austrokiwi1
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Post by austrokiwi1 »

I assume you are referring to your Pen F. Immediately on reading your resonse specifically the quoted part I have questions ( some of them long standing):
Austrokiwi, Macrero, if I want to fully utilize my MFT sensor at 50-80Mp, the lens must have an effective aperture wider than f8
First a base assumption of mine, which is: the pen F has a 20 mp sensor and that is the Pixel density that dictates when diffraction sets in (not the apparant resolution when you use your cameras sensor shift technology). I assume you are thinking the same way as you are working with the assumed DLA of F8. I understand, from Cambridge colours advanced DLA calculator, that a 50MP MFT sensor would have a DLA of F4.

As a reminder I use a Sony A7rII and an OLY OMD-EM10II. Although the 16MP Oly has slightly smaller pixel size, I treat both cameras as having a DLA of F8 ( diffraction starts just "above" F6 for both cameras). So I too prefer fast lenses of F 2 or F2.8.

So my main questions are:
1: Although I think not, does the sensor shift technique actually extend the DLA to an aperture smaller than F8. MY thinking here is that the sensor shift may emulate a sensor with a larger pixel size( and therefore larger airy disk).

2. When do you need to go to a resolution of 50-80 MP? My question is based on wanting to know for what media you are producing the pictures. I find I only need the 42mp of the sony A7r when producing high quality print media(full sized images). For online posting the A7rII's resolution is somewhat of a liability. Most websites have such small file size allocations that the Photos from the A7rII look worse than those produced from an average APSc DSLR. The reason being the photos require greater reduction which results in greater picture degradation. Likewise my experience with journal articles is that the publishers limits see the photos looking degraded when compared to the supplied originals.

3. I sometimes have the impression that you are trying to compete with the 35mm format? By way of a loose analogy: It seems you have an Nascar rated vehicle but are trying to drive it like it is formula one car. This impression may be directly related to how I use the two different formats. I find the MFT camera has an advantage directly relating to the small sensor size. For an equivalent FOV I can use much lower magnification resulting in less noise and a deeper DOF. I find my MFT camera excels in the close up range producing photographs that, online, look like higher magnification FF images. I often wonder whether given the direction you seem to be taking with your macro and micro photos that you might be better off with stepping up to a fullframe system. I assure you from my experience the greater dynamic range, and significantly lower noise is very noticeable. I would be even stronger in this viewpoint if the rumours about next years release of the A7rIII are correct ( touch screen, dual card slots and a 60- 70mp sensor)
Still learning,
Cameras' Sony A7rII, OLympus OMD-EM10II
Macro lenses: Printing nikkor 105mm, Sony FE 90mm F2.8 Macro G, Schneider Kreuznach Makro Iris 50mm , 2.8, Schnieder Kreuznach APO Componon HM 40mm F2.8 , Mamiya 645 120mm F4 Macro ( used with mirex tilt shift adapter), Olympus 135mm 4.5 bellows lens, Oly 80mm bellows lens, Olympus 60mm F2.8

Lou Jost
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Post by Lou Jost »

Austrokiwi, thanks for the detailed and thoughtful comment. You are right to question why I care about high resolution. But I hope to publish in coffee-table books and glossy magazines (I had a large spread in Sports Illustrated back in the film era), and have also had gallery exhibits of large prints, so it makes sense for me.

I switched from FF to MFT because of the weight of the equipment for fieldwork. I just can't carry my beautiful fast 400mm FF Nikkor super-telephoto and required massive tripod, plus macro and scenery lenses, up mountains any more.

Leaving aside issues of noise and dynamic range for the moment, in terms of resolution and diffraction, using coupled lenses, for a given field of view and number of pixels, the sensor size doesn't matter. The extra magnification needed for FF exactly cancels the smaller aperture you can use.

One advantage of FF is that because you need a larger magnification for a given image, there is not much of an EA advantage for coupled lenses versus lenses-on-extension. The advantage of coupled lenses is large at 1:1 but not so large at 2:1, and negligible at 4:1. So for some FOVs you do have more lens options than I have.

In high-res mode on the Olympus, the noise is not too much greater than FF; if sensor-shifting were perfect (which it isn't), the 8 shots per image gather more total light than a single FF image of the same FOV.

As you know, mirrorless cameras are obviously ideal for microscopy. For specimens in liquid, it is also useful to eliminate shutter vibrations, and an electronic shutter is ideal for this. And if one does a lot of stacking, worries bout shutter wear are gone. Our Olympus set to Silent Shutter are wonderful tools for deep stacks and stitching of microscopic objects.

In terms of bit depth, the Sony A7RII when used with electronic shutter drops its files to the same bit depth as the Oly, as far as I can tell. Also you cannot use it with flash, as I can with my PEN F.

I am glad to hear the rumors of a new Sony. Hope they fix the electronic shutter incompatibility with flash (the PEN F proves it can be done, even with cheap Yongnuo flashes not connected to the camera, so it isn't hard) and I hope they stop downgrading the file depth when that shutter is used. I'd buy it as a studio camera. At present I use Nikon APS (with mirror taped in the up poistion) and MFT interchangeably, depending on the subject. Most of the lenses are usable on both systems, and would also be usable on Sony E-mounts. Having multiple formats can take the place of multiple lenses for different angular fields of view.

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