LA-EA1 adapter design flaw.

Started Nov 6, 2010 | Discussions
b_z New Member • Posts: 19
LA-EA1 adapter design flaw.

Sony LA-EA1 official A/E mount adapter has a huge design flaw ruining bokeh quality with fast lenses (faster than f/2).

The adapter has a chamber which is really smaller than Sony reflex ones, and it prevent portions of light to get to the sensor. It's very easy to spot on defocused lights, and really disturbing for bokeh fans (who I believe are the users of 50/1.4, 85/1.4, 135/1.8 lenses).

Here are some examples where it shows, one of them is a realistic portrait, the others are pure tests with those lenses :
-Samyang 85/1.4
-Sony 50/1.4
-Sony 135/1.8

1

I also tested Zeiss 85/1.4 which shows the same problem, and Zeiss 24/2, wich shows it too, but it's a lot less noticeable (bokeh disks are smaller, and it only appear at the extreme border of the frame).

I doesn't occur at all when lenses are stopped down to f/2.8 and smaller or with any 2.8 or slower lens.

I showed it to Sony staff member in French "Salon de la photo" yesterday, they told me they were not aware of this issue.

Some other LA-EA1 user confirmed this with other fast lenses, both in photographs and videos. Try it yourself if you have one.

The cause is the narrow chamber which obstructs light, don't bother to search for something else.

I myself wonder if I won't ask for a reimbursement, I bought this adapter for the sole purpose of using super-fast alpha lenses on my Nex, I'm extremely disappointed...

hotwire Regular Member • Posts: 305
Re: LA-EA1 adapter design flaw.

I've seen this issue come up with the Canon 85L on crop bodies. It's not unheard of, but I agree it's not exactly a desirable trait.

How long till someone takes a dremmel to it?

OP b_z New Member • Posts: 19
Re: LA-EA1 adapter design flaw.

hotwire wrote:

I've seen this issue come up with the Canon 85L on crop bodies. It's not unheard of, but I agree it's not exactly a desirable trait.

How long till someone takes a dremmel to it?

Wait till the guarantee is over ? ^^

I don't think it's possible, there is some elctronic and mechanics in this adapter, dremmeling it could ruin that... For the Samyang one could buy some chinese adapter, but for other lenses aperture control and EXIFs are intersting. (SAM and SSM autofocus is a joke, it won't bother me to lose it..)

deyo81 Junior Member • Posts: 28
Re: LA-EA1 adapter design flaw.

Ugly...
--
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docmaas
docmaas Veteran Member • Posts: 7,030
Re: LA-EA1 adapter design flaw.

Looking at my own copy I fail to see why they created that small square tunnel at all.

It wouldn't surprise me at all if a great deal of that material could be removed but you'd have to disassemble it first to make sure you don't hurt any connections or chips that may be inside.

It does appear to be a poor design but it's hard to say how long sony might take to fix it.

Mike
--

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GaryW Veteran Member • Posts: 9,667
Making lemonade...

This is a bit disappointing, although it sounds like it won't affect me much (as my fastest lens is the 50/1.7 and it's not exactly great at f1.7).

Still, it made me wonder. If the box can change the shape of the bokeh, what else can change the shape? Ok, I know you'll lose the f1.2, but I would be curious if we could make a poor-man's STF. Am I crazy?

I forget the term for the shaded disk used in the STF. I've seen other designs, such as disks used in the lensbabies. You can even use cutouts in front of the lens and have interesting effects, but I had inconsistent results.
--
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Tikkis Junior Member • Posts: 44
Re: Making lemonade...

GaryW wrote:

Still, it made me wonder. If the box can change the shape of the bokeh, what else can change the shape? Ok, I know you'll lose the f1.2, but I would be curious if we could make a poor-man's STF. Am I crazy?

Sorry to butt into the discussion, but what is STF. I guess it's quite obvious for all the native english speakers, but being a foreigner, I'm at loss.

Tikkis

sajah Forum Member • Posts: 63
Re: Making lemonade...

"Smooth Trans Focus", Minolta's term. Read here for more info: http://www.dyxum.com/columns/articles/lenses/sal-135f28/sony-af-135-stf-sal-135f28_review.asp

GaryW Veteran Member • Posts: 9,667
Re: Making lemonade...

"apodization element" was the term I was looking for. Looks from the diagram like it needs to go into the aperture part of the lens, ideally.

Here's a link showing how to modify bokeh with shapes in front of a lens. http://www.diyphotography.net/diy_create_your_own_bokeh

Either in front or behind the lens, I'd assume there'd be distortion.
--
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KEITH-C Forum Pro • Posts: 14,131
Re: Making lemonade...

This particular issue is more evidence that Sony rushed out the NEX before thorough testing ? This is potentially more serious than the failure to display magnified LCD images when using 3rd party lenses.

Has anyone got a picture of the offending baffle in the adaptor ? This seems counter-intuitive as I would have assumed , without much thought , that cutting out extraneous light ( needed by a FF sensor ) woud cut down on any potential flare & this would be desirable.
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Kiril Karaatanasov Senior Member • Posts: 2,203
My own research

Ok I did some experiments with NEX and several lenses.

50/1.7, 70-210/4 (has huge back lens), 85/1.4

Experimenting for half an hour with multiple bokeh generating situations I was able to reproduce the problem only 1 time! I was using 85/1.4 @ 1.4

now when I closed it down to 1.7 the problem is gone

Provided that 85/1.4 sits very very funny on NEX and weighs about 3 times as much as the camera this si not an issue you will notice in reality very often if at all. also notes that on 85/1.4 bokeh is mostly unaffected i.e. out of 30 or so situations I go the problem only 1 time on a very specific object that has irregular shape!

135/1.8 the other possibly impacted lens is even more hilarious mounted on NEX as it is 2 times bigger than 85/1.4

even on those impacted lenses closing to 1.7 seems to solve the issue completely.

So thanks for noting this problem. It is great to know and recognize but I am not throwing my nex on e-bay over this.

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OP b_z New Member • Posts: 19
Re: Making lemonade...

GaryW wrote:

"apodization element" was the term I was looking for. Looks from the diagram like it needs to go into the aperture part of the lens, ideally.

Here's a link showing how to modify bokeh with shapes in front of a lens. http://www.diyphotography.net/diy_create_your_own_bokeh

Either in front or behind the lens, I'd assume there'd be distortion.
--
Gary W.

I'm a bokeh fan/contol freak, I love STF too

But the apodization element HAS TO be in the aperture plane, or it will make either strange bokeh (in the same way as this adapter, more likely if it's behind the lens) or vignetting (more likely if it's in front) or both.

OP b_z New Member • Posts: 19
Re: My own research

The problem appears on both of the photographs you posted.

It only appears on border of the frame, the wider the aperture, the more it appears closer to the center too. It's more easily seen on ponctual lights that are out of focus (and I expect it to be stronger on lights before focus than lights after focus, but I haven't made any calculations yet). Your bokeh has no such ponctual light that stands out, but go out at night and take close portraits at f/1.4 with city lights all over the frame. You'll be surprised by the look of those in border of the frame.

I personnaly think zeiss 85/1.4 (or samyang or minolta equivalents) are a pleasure to use on the Nex dispite their weight and size. I agree STF or Zeiss 135mm are too heavy but their size is almost on par with E-mount 18-200 !

GodSpeaks
GodSpeaks Forum Pro • Posts: 14,642
So not likely a problem with a Voightlander 15mm f4.5 then

But to be honest, I think this is a tempest in a teapot. The lenses you are complaining about being effected are really designed for full frame cameras and should be used on those FF bodies.

Attaching them to an NEX defeats the entire purpose of the NEX... small compact size .

But to each their own.

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KEITH-C Forum Pro • Posts: 14,131
Re: So not likely a problem with a Voightlander 15mm f4.5 then

While there is some truth in saying that large ,wide aperture lenses are inappropriate for the NEX it is perfectly valid to point out the limitations of such combinations. Remember that Sony used some of these lenses when publicising the versatility of the NEX
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Karsten Meyer
Karsten Meyer Contributing Member • Posts: 811
Re: LA-EA1 adapter design flaw.

Hello,

from a logical point of view it can only affect lenses where the rear lens has a bigger diameter than the height of this tunnel - about 22 mm. With bigger lenses the tunnel schould act like an aperture, right?

Best Regards,
Karsten

OP b_z New Member • Posts: 19
Re: So not likely a problem with a Voightlander 15mm f4.5 then

GodSpeaks wrote:

But to be honest, I think this is a tempest in a teapot. The lenses you are complaining about being effected are really designed for full frame cameras and should be used on those FF bodies.

I disagree with that. As a bokeh fan, except for 135 STF, I consider almost of of Sony fast primes give better result on apsc than on full frame. On FF the swirling bokeh (bokeh discs turn into cats eyes shapes) is disturbing, on apsc it's almost gone.

Attaching them to an NEX defeats the entire purpose of the NEX... small compact size .

This is the sole purpose of this adapter in my opinion... So in regard of this product, its a huge concern.

But to each their own.

Of course, I'm just speaking as a bokeh fan/control freak but I guess most LAEA1 users will share my deception.

GaryW Veteran Member • Posts: 9,667
Re: LA-EA1 adapter design flaw.

Karsten Meyer wrote:

Hello,

from a logical point of view it can only affect lenses where the rear lens has a bigger diameter than the height of this tunnel - about 22 mm. With bigger lenses the tunnel schould act like an aperture, right?

It may also depend upon the distance of the rear lens from this "aperture". The further the lens is from the "tunnel" the larger it can be, and still have light angling towards the sensor. I wonder if close vs. infinity focus also changes this behavior?

Best Regards,
Karsten

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Gary W.

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OP b_z New Member • Posts: 19
Re: LA-EA1 adapter design flaw.

GaryW wrote:

Karsten Meyer wrote:

Hello,

from a logical point of view it can only affect lenses where the rear lens has a bigger diameter than the height of this tunnel - about 22 mm. With bigger lenses the tunnel schould act like an aperture, right?

It may also depend upon the distance of the rear lens from this "aperture". The further the lens is from the "tunnel" the larger it can be, and still have light angling towards the sensor. I wonder if close vs. infinity focus also changes this behavior?

With "classical" prime lense I think it should be worse when focused at infinity and with a ponctual light in the foreground. But I'm not absolutely sure.

I also think it should bring additional vigntting, and not in the usual radial pattern, but I can't verify this since I don't personnaly own such a lens...

Best Regards,
Karsten

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Gary W.

GaryW Veteran Member • Posts: 9,667
Re: LA-EA1 adapter design flaw.

I just tried a quick test with my Minolta 50/1.7 at min. focus and at f1.7 shooting at a couple of different windows/views, and I don't see the flat spots on the round bokeh circles. Perhaps I don't have the ideal lighting to show the problem, but this may be lens-dependent. I can see where this would be really annoying for f1.4 a-mount fans, though. I can't use the 1.7 at f1.7 anyways -- it needs to be stopped down a bit for better results.
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