Sigma 19mm F2.8 pretty usable with A7

[enzoshadow]

The result seems pretty usable for my standard considering it was only $100 when it was on sale last year, but what do you guys think?




F2.8




F2.8




F11




F22

 

[viking79]

Thanks! I don't have the 19mm any more. If you look through the lens with both caps off you should be able to see where the image is being blocked first (look through the front or back straight through, then start rotating it off to one side).

On the Sigma 60mm I was able to expand the image circle significantly by removing the rear baffle (flare performance will probably be much worse now, but haven't tested). Just 3 small screws hold in the baffle on that lens.

The remaining issue with the 60mm is actually the plastic holder for the rear element group. It could maybe be modified to get even more image circle. A small update to the 60mm from Sigma would probably let it work full frame. I don't think it would take them much R&D money.

Eric

 

[Murx]

F22

Pretty cool !

What you are seeing (black circle), is most likely the rear baffle. I would think that the sigma 19mm actually covers the whole FF sensor. Could you or anyone else validate that hypothesis ? I just unscrewed the three screws on my Sigma 19mm for testing - trivial effort and the baffle certainly is a physical obstruction.

If that really works, that would strongly influence my A7(R) buying decision ...
(and not just mine i think)

Thanks !!!

Murx

 

[120 to 35]

Thanks for posting the test shots. Up to full-height square crops should look quite acceptable, which adds to the usefulness of the lens on the A7.

 

[Hin Man]

Thanks! I don't have the 19mm any more. If you look through the lens with both caps off you should be able to see where the image is being blocked first (look through the front or back straight through, then start rotating it off to one side).

On the Sigma 60mm I was able to expand the image circle significantly by removing the rear baffle (flare performance will probably be much worse now, but haven't tested). Just 3 small screws hold in the baffle on that lens.

The remaining issue with the 60mm is actually the plastic holder for the rear element group. It could maybe be modified to get even more image circle. A small update to the 60mm from Sigma would probably let it work full frame. I don't think it would take them much R&D money.

Eric

Eric,

Whenever time allows, please post a sample shot with your Sigma 60mm in the normal FF mode and not the crop mode. This can be a great gem with AF goodness for $239. I have both the older version Sigma 19 and 30. And my A7 is coming this morning or Monday.

Any sample picture with Sigma 60 in non-crop mode may give me a reason to buy the Sigma 60 with a good excuse. I love the Sigma Art series as they are the best value lens in the E mount in my book.

Cheers,

Hin

--
learning: http://www.techtheman.com
personal: http://hintheman.blogspot.com/

 

[Hin Man]

F22

Pretty cool !

What you are seeing (black circle), is most likely the rear baffle. I would think that the sigma 19mm actually covers the whole FF sensor. Could you or anyone else validate that hypothesis ? I just unscrewed the three screws on my Sigma 19mm for testing - trivial effort and the baffle certainly is a physical obstruction.

If that really works, that would strongly influence my A7(R) buying decision ...
(and not just mine i think)

Thanks !!!

Murx

+1 as mine is coming in the morning. And you see my testing with 19 and 30 without the baffle hopefully in the weekend. If not, sometime early next week.

Cheers,

Hin

--
learning: http://www.techtheman.com
personal: http://hintheman.blogspot.com/

 

[Keit ll]

There isn't a rear baffle on my Sigma 19 mm ?

 

[Murx]

There isn't a rear baffle on my Sigma 19 mm ?

This is the rear of the sigma 19mm. There are three screws - remove screws and the baffle comes out (this is a circular baffle - not a rectangular one - still a baffle).

Judging by how tightly this baffle covers the rear element, i believe that the black circle of the above test shots is caused by this baffle ...

 

[Russell Evans]

Translate DCHome, Sigma 30mm baffle removed used on A7

Thank you
Russell

 

[Keit ll]

I see what you mean but I doubt if this 'baffle' affects the light path , however I will be interested to see your results , hope it works !

 

[MG Nivard]

If i understand that translated japanese page correctly the 30mm sigma covers FF up to about F5.6 without the baffle?

wow this could mean they could pretty easily adapt these DN lenses for the A7(R), just redesign the outer shell and realign some stuff a bit.

 

[Murx]

Huh -

I need a "translate google-translate function" ;-)
For the sigma 30 mm i think the answer is - "better -- but not good enough .. ?"

 

[Russell Evans]

Huh -

I need a "translate google-translate function" ;-)
For the sigma 30 mm i think the answer is - "better -- but not good enough .. ?"

You might not get 30mm, but a crop to remove the vignetting would probably give you about the FOV of a 35mm with maybe about 85-90% of the pixels intact. That's not too bad for a f2.8 lens a lot of people only paid $99 for. You could always buy the $800 FE 35mm f2.8 to get all the pixels.

Thank you
Russell

 

[Hin Man]

Huh -

I need a "translate google-translate function" ;-)
For the sigma 30 mm i think the answer is - "better -- but not good enough .. ?"

You might not get 30mm, but a crop to remove the vignetting would probably give you about the FOV of a 35mm with maybe about 85-90% of the pixels intact. That's not too bad for a f2.8 lens a lot of people only paid $99 for. You could always buy the $800 FE 35mm f2.8 to get all the pixels.

Thank you
Russell

My problem is that I already ordered the $800 FE 35mm f/2.8. And the lens and the A7 is coming this morning if the UPS driver is on time; otherwise, it is no delivery as I have to leave for work and lunch appointment. I will report back how it goes. If I can use my best value Sigma 30mm f/2.8 to 90%, I will likely think about saving that $800 and replace it with something cheap as in a $300 with manual focus as an interim solution until Sigma react with a true FE lens.

Big Cheers, (I have +1 liking on all people who helps in this thread)

Hin

 

[Murx]

My problem is that I already ordered the $800 FE 35mm f/2.8. And the lens and the A7 is coming this morning if the UPS driver is on time; otherwise, it is no delivery as I have to leave for work and lunch appointment. I will report back how it goes. If I can use my best value Sigma 30mm f/2.8 to 90%, I will likely think about saving that $800 and replace it with something cheap as in a $300 with manual focus as an interim solution until Sigma react with a true FE lens.

Big Cheers, (I have +1 liking on all people who helps in this thread)

Hin

Advice: shoot 16:9 with the sigma 30 (sans baffle), buy a CZJ Flektogon 2.4/35 or a Distagon 28/2.8 for MF, throw a party with the rest of the money.

And after the party you can also tell me how that Flektogon/Distagon is working out with your A7...

 

[Keit ll]

If the Sigma's come close to covering the FF sensor then that bodes well for similar designs of a series of proper FF Sigma lenses ?

 

[Hin Man]

My next day delivery from UPS fails me. I ordered on Wednesday. This is not the first time that I have a grudge against the brown truck. I always prefer fedex or USPS priority and none of those are cheap enough for me to splurge for next day delivery.

Anyway, I don't have my A7 to test 19 and 30 without the baffle, I wish some kind souls such as OP or viking79 can help out.

Cheers,

Hin

 

[Hin Man]

http://www.dchome.net/forum.php?mod=viewthread&tid=1234863&extra=page=1

The comment #10 have a bunch of shots with the removal of the baffle. Looks promising in f/2.8 to f/8.0, the severe vignette happen in f/22 in the sample. f/5.6 is good to use for most cases -- I think. But I can't tell until more tests come.

Cheers,

Hin

 

[Keit ll]

http://www.dchome.net/forum.php?mod=viewthread&tid=1234863&extra=page=1

The comment #10 have a bunch of shots with the removal of the baffle. Looks promising in f/2.8 to f/8.0, the severe vignette happen in f/22 in the sample. f/5.6 is good to use for most cases -- I think. But I can't tell until more tests come.

I have downloaded an example from the link shown above & then applied some Vignetting/perspective/colour correction to show what can be achieved . The photo was shot using Sigma 30mm on A7 camera at F8.0 - the back baffle had been removed.


F 8.0 original from dchrome.net link


some correction applied as described above ,still with slight hint of Vignetting but which would be unnoticeable in many shots ?

 

[Hin Man]

http://www.dchome.net/forum.php?mod=viewthread&tid=1234863&extra=page=1

The comment #10 have a bunch of shots with the removal of the baffle. Looks promising in f/2.8 to f/8.0, the severe vignette happen in f/22 in the sample. f/5.6 is good to use for most cases -- I think. But I can't tell until more tests come.

I have downloaded an example from the link shown above & then applied some Vignetting/perspective/colour correction to show what can be achieved . The photo was shot using Sigma 30mm on A7 camera at F8.0


F 8.0 original from dchrome.net link


some correction applied as described above ,still with slight hint of Vignetting but which would be unnoticeable in many shots ?

Great work, it is very promising. I wish I have my A7 and I will be all over it as it is in my best interest that a good series of 19/30/60 with the art series can work like 90% in FF with some loss of detail on the corner. I don't mind as I want a solution until Sigma or other great companies staff up the FE mount like the E mount. I will keep my FE 35mm f/2.8 that I order but I don't like the full pricing of $800 a piece. With a $800 pricing, I expect something as in FE 35mm f/2.0. And I don't need OSS in a 35mm with fast speed. I need AF though; otherwise, I would have gone to Voiglander 35mm f/1.4 or something similar in the $600 range.

I will for sure upgrade how I find out with my 19 and 30. And I know viking79 and other great folks will help out on this nice discovery. If that works well, it will push me to buy without hesitation on the Sigma 60mm f/2.8 for sure to be shared between my NEX and A7.

Cheers and Thanks,

Hin

--
learning: http://www.techtheman.com
personal: http://hintheman.blogspot.com/