Difference in Lens Adapter Question

[Swandy]

I have the EP2 with both the original Olympus OM - 4/3 adapter and the Olympus 4/3 - m4/3 adapter. I have been using this combination with a Lensbaby Composer and a few old Olympus OM Zuiko lenses.

Does anybody know if there an advantage - either image quality, exposure, sharpness, focusing distance, etc. - to use the Olympus OM - m4/3 adapter? (Aside from having to use one adapter vs. two.)

Thanks,
Steve

 

[lchien]

Technically it should work identically. But Any errors or tolerances in co-planarity (affecting side-to side focus uniformity) and thickness tolerance affecting infinity focus point (and there are always some) will be doubled when you use two adapters.

If the tolerance errors are small enough there should be no problems.
Since no-name OM- M43 adapter can be had for under $10 (link below for $8.99 adapter) maybe you should not try to cut corners. But then, the cheap ones might be where the tolerance problems creep in.

Olympus OM to Micro 4/3 M43 Lens Mount Adapter EP3 GF5 GX1 EPL5 OM-D E-M5 OM-M43

Semi- name brands like Fotasy and Fotodiox are around $20 and under.
https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias=aps&field-keywords=OM-M43+adapter

 

[gnarlydog australia]

Technically it should work identically. But Any errors or tolerances in co-planarity (affecting side-to side focus uniformity) and thickness tolerance affecting infinity focus point (and there are always some) will be doubled when you use two adapters.

If the tolerance errors are small enough there should be no problems.
Since no-name OM- M43 adapter can be had for under $10 (link below for $8.99 adapter) maybe you should not try to cut corners. But then, the cheap ones might be where the tolerance problems creep in.

Olympus OM to Micro 4/3 M43 Lens Mount Adapter EP3 GF5 GX1 EPL5 OM-D E-M5 OM-M43

Semi- name brands like Fotasy and Fotodiox are around $20 and under.
https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias=aps&field-keywords=OM-M43+adapter

hmmm, I always wondered about co-planarity (big word, for me) tolerances of adapters.
Then I went mentally back to my college days where we used to shoot with bench cameras (bellows type) and all sort of adjustments were possible and I am pretty sure the focal plane was never 100% level with film, even if one wanted to have it. However never noticed any DOF/focus problems or image distortion.
I also make my own adapters and shave aluminium rings to then glue them onto C-mount bases for vintage lenses that have no commercial adapters made for them.
I am sure my shaving is never as precise as the worse Chinese el-cheapo adapter.
And I still fail to see any difference between images on a factory made (but bulky) Exakta mount adapter and mine DIY (but slim) one, with the same lens.

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Trioplan on DIY adapter_3 by gnarlydog, on Flickr

What am I missing?

 

[barry]

Wider angle lenses will show problems more easily than tele's.

 

[gnarlydog australia]

Wider angle lenses will show problems more easily than tele's.

I thought so
But there aren't many adaptable legacy/vintage wide angles (in M4/3 speak that is 17mm or wider) to have, or they really aren't worth trying?
SLR wide angle lenses that are really short are mighty expensive, so in that case one could justify a superbly machined adapter. For the garden variety nifty-fifty a slightly less perfect (or so perceived) adapter is sufficient?
Has anybody tried and come up with conclusive visible difference between cheap adapters and expensive ones?
I don't have any expensive adapters so would be nice to know/see...

 

[HarryS]

My first foray into adapted lenses on M43 was sticking the Olympus OM-43 adapter onto the Panasonic DMW-MA1. I thought the combo works well, and is well made. While I got the OM adapter for free from Olympus, they sold it for $100, while the Panasonic adapter was $119 in 2010. Good parts.

If one makes a habit of shooting test charts for reviews and testing of old lenses, I'm sure the flatness issue will show up. I've made a couple of home made adapters myself, which weren't available in the marketplace, and I'm just happy to be able to use those lenses.

 

[barry]

Has anybody tried and come up with conclusive visible difference between cheap adapters and expensive ones?

There's a fairly recent discussion in the m.ZD 9-18mm thread where someone was having a severe problem with his lens, which turned out to be ZD 4/3 9-18mm on a cheaper adapter. Replacing the adapter with an Oly or Pana fixed it.

But I don't remember seeing any complaints like that with longer lenses... Just some complaints about infinity focus...

 

[gnarlydog australia]

But I don't remember seeing any complaints like that with longer lenses... Just some complaints about infinity focus...

the very reason I started to make some M42 adapters myself since some cheap ones (Fotga) were about 1mm too short.
I now use M42 macro extension tubes cut down the correct length and epoxy glue (JB Weld) onto C-mount adapters: lighter and less bulky with perfect infinity stop where it's meant to be
Here shows M42 adapter discrepancies between brands

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image_4 by gnarlydog, on Flickr

 

[panamike]

With these apparent discrepancy's but most adapters still working does this mean the depth of focus (not DOF) on m4/3 is fairly large in relative terms.

 

[Petrochemist]

With these apparent discrepancy's but most adapters still working does this mean the depth of focus (not DOF) on m4/3 is fairly large in relative terms.

No it just means the focus needs adjusting to compensate.
Using cheap adapters lenses will focus on infinity with the lens scale set to a shorter distance and experience a corresponding increase in the minimum focal distance.
As has been said above the effect is more noticeable at shorter focal lengths - I had to turn the focus ring nearly all the way to minimum to get infinity focused on my adapted 10mm lens!

 

[gnarlydog australia]

No it just means the focus needs adjusting to compensate.
Using cheap adapters lenses will focus on infinity with the lens scale set to a shorter distance and experience a corresponding increase in the minimum focal distance.
As has been said above the effect is more noticeable at shorter focal lengths - I had to turn the focus ring nearly all the way to minimum to get infinity focused on my adapted 10mm lens!

an adapted 10mm lens: that is very interesting.
Which one and are you happy with the results it gives you?

 

[PakkyT]

With these apparent discrepancy's but most adapters still working does this mean the depth of focus (not DOF) on m4/3 is fairly large in relative terms.

I think it really depends on the lens, or more specifically, the focal length of the lens being used. I had the same issue @gnarlydog australia dog experienced with a Fotga m42 adapter I bought to adapt my Peleng 8mm fisheye onto my E-M1. It was off by a hair under 1mm and that was enough that the ENTIRE focusing range of the Peleng was outside where it should have been (the entire focus range was blurry). I had a plastic shim printed up (3D printer at work) to go between the adapter and the lens to put that roughly 1mm space back in place and now the lens focuses perfectly through the entire focus adjustment.

Here is the setup with the red colored spacer ring in place...

Red Spacer Ring for M42 adapter

• PakkyT
• Nov 1, 2015

Peleng 8mm fish eye lens, spacer, then FOTGA M42 to u43 adapter.

 

[Petrochemist]

an adapted 10mm lens: that is very interesting.
Which one and are you happy with the results it gives you?

It was a Samyang 10mm f2.8 that the seller didn't know the mount for, so was temptingly cheap.
Unlike PakkyT I've only tried a bit of card for packing it out, so results have been disappointing.
At some point I'll have a better go at shimming the adapter, or sell the lens!

 

[lchien]

OK, here is the listing of Flange-Focal distance from Wikipedia for a whole bunch of different camera systems. This is the lens flange to the image plane distance.
Flange focal distance - Wikipedia, the free encyclopedia
the link lists the F-F distance for Many camera systems inlcuding 6x6 an 6x7, but the ones I was looking for are:
M43 - 19.25 mm
4/3 - 38.67 mm
OM system - 46.00 mm

That tells us that the Thickness of the adapters should be precisely:
OM-M43 - 26.75 mm
4/3 to M43 - 19.42 mm
Adapters with those dimensions will put the flange of the adapted lens at the specified systems' Flange-focal distance from the micro 4/3 sensor plane.

I have the equipment to measure both coplanarity and absolute thickness properly, I will get it set up tomorrow - dial gauge, calibers, 1-2-3 reference blocks, dial gauge stands, granite surface plate.

A quick look with some calipers at an Fotasy OM-M43 adapter gives me about 26.69 to 26.71 mm thick - its hard with the calipers because its thickness is at different diameters making the calipers jaws tilt a bit.
But it appears to be short about .04 or .06 mm, or about .0015" to .0023
A second unit from BIG-IS measured spot on 26.75mm

+/-.001" and +/-.1 mm are typical industrial machining tolerances for things like this. Remember some of these are sub $10 assemblies.

Being short allows focusing past infinity which is better than being long, and not being able to hit infinity. I wonder if they purposely have a tolerance like +.000"/-.002" on the 26.75 dimension to ensure infinity focusing.
I have several adapters of both kinds so I will check them hopefully as well as get a better handle on the exact errors.

Given that we can either use autofocus or manual focusing aids like Peaking, the absolute marking of the distance on the lens is not as important as being able to move the focus over the entire range.

Some lenses move the elements as much as an inch when changing focusing from close to infinity. Does .001" make much difference in that scheme? Seems like as long as it covers infinity then losing .001 inch of coverage at the minimum focusing distance is not too critical. There always extension tubes.

 

[lchien]

Here's the Measurement results

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First of all two FOTGA OM adapters are complete busts - they are made to the wrong flange to flange distance... I measured 25.97 mm which tells me the intended was probably 26 mm but the correct value should be 26.75 mm.

But other than that the numbers seem reasonable. I'm not sure how much difference .05 mm makes.
I do note the 4/3 adapters have a significantly larger net error than the OM adapters.

 

[tkbslc]

The adapter being a little too short is preferable. You will create a longer MFD, but at least Infinity is still possible. If the adapter is too thick, it becomes a minor extension tube and you lose infinity.