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Old Apr 10, 2012, 05:07 PM
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the Sigma 19mm lens on the Sony nex5n/nex7

Hi.
I have been a satisfied owner of a Sony Nex5n for a few months now. I use it mainly for aerial video, not so much photo. I have used the camera a lot, some of the footage has been used on national television and the production companies has no complaints about the image quality.

However, the one thing that bugs me is that I have felt the video is a bit more blurry than I would have preferred. I use the pancake lens and I have heard other complaints about the same issue too. The Carl Zeiss lens is a sollution I guess but the price tag is too big for my taste.

So, here comes the cheap Sigma 19mm lens and I hear reports its supposed to be sharper than the stock pancake.

Here is a short review that doesnt say much.
And here is a comparison between the two that is more useful.

What I really want, is to hear from you. Have any of you tried it and can share experiences, videos, pics and so on....
-------------------------------------------------------------------------------------------------------------
EDIT: Below is my complete review which I also has posted in post #30:

Here is my conclusion after testing the Sony 16mm and the Sigma 19mm extensively for a few days now. I have only focused on the lenses shooting video since I am not that much into aerial photo.

First, here is the testvideo.
This testvideo shows the two lenses side by side. I must state though, that these videos doesnt give you the reight impression on all aspects I will write below, mainly because I didnt find the absolutely perfect focuspoint when setting up the cameras. They are slightly out of focus.

Test: Sony 16mm and Sigma 19mm on a Sony Nex5n camera (2 min 20 sec)


I find it hard to shout out loud and clear which lens is best. Its a matter of weighing their qualities up against each other. The main difference lies in weight (important for us), field of view, colors and sharpness.

The main reason for choosing the Sony for me would be:
-it weighs 65 g compared to 143 g for the Sigma
-it is wider which I prefer for aerial video. Not only because it gets a wider view, but a wider field of view also means it masks unstable movements more
-it handles autofocus well on aerial filming, while the Sigma doesnt handle autofocus while filming at all. It jitters and vibrates in and out of focus all the time. Some might say you could just find the hyperfocal point (put the camera at f8 and focus close to infinity and its focused almost all over the field of depth), but it takes a lot of testing to find that perfect spot. For some tasks the AF is very useful too, if you are filming very close and far away on the same ride.

The main reason for choosing the Sigma is:
-the colors are stronger and the contrast is better. The Sony seems a little washed out, bleached. Its not about sharpness really, its more like you can see more details and nuances. For example when you are filming big freen lawns. When filming a green lawn with the Sony its kind of a big grey mass while filming with the Sigma you see a lot more details and nuances of green. Sadly that didnt come through in this video but I have a lot of examples in my videofiles here on my mac.
-The sharpness is better, not extremely much better but very noticeable still.

Conclusion:
So which one will I choose for aerial filming? I am simply not sure. The Sigma kind of feels like a much better lens optically. It simply gives you better videoquality. Then again the Sony has some practical advantages which is nice when you are gonna lift it with a copter. Both lenses are pretty cheap so I might go for both and take the time to find out which will be used the most.
If you are relly serious you might wanna go a few steps further up on quality and choose the Voigtlander 15mm lens or a Carl Zeiss lens. I have tried the Voiglander and it impressed me very much. To be able to mount it to the Nex it will cost you about 1000 USD though.
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Last edited by babanan; Apr 14, 2012 at 03:13 PM.
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Old Apr 11, 2012, 01:13 AM
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I am interested as well.....
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Old Apr 11, 2012, 01:32 AM
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I know that power has ordered one for himself, so he'll probably be the first to put one up in the air!

http://www.rcgroups.com/forums/showp...&postcount=278

I've got a 16mm on the way, and have also bought the fisheye converter to experiment with spherical panoramas:

http://www.panoguide.com/forums/qna/9196/

Cheers


David
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Old Apr 11, 2012, 04:17 AM
Begin with end in mind...
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I expect my Sigma 19mm this week, tomorrow would be good I will post some samples when it arrives...


Mike
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Old Apr 11, 2012, 08:02 AM
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I just couldnt wait so I went to a local store and bought the lens just now. I will post my first impressions later today. I hope the reviews are true, that this lens in fact is sharper than the stock lens. For me thats the only purpose for doing this.

What about you Power? Why did you buy this one?
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Old Apr 11, 2012, 08:44 AM
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I did the first test just now and I must say the first impression was absolutely horrible. It seems like the lens cant handle the autofocus at all during video-recording. It jumps in and out of focus and the image is vibrating in a very strange way. Icross-checked with my Sony pancake and it did fine regarding these issues. Thats a pity because the autofocus has done a great job for me with the Nex5n and I want to continue using it. The lens seens to act normal with manual focus. Remeber though, I havent gone in depth yet to find out what causes this.
I also did some photos but I havent studied them yet. Everything looks normal with the photos but Ill come back with more later.

Here is the sample video:
Lenstest Sigma 19mm on a Sony Nex5n (0 min 13 sec)
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Old Apr 11, 2012, 12:17 PM
Begin with end in mind...
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Eagle Lake, Minnesota
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Looks like you are getting AF motor noise Something is not right...IMO I don't think Sigma would release a lens on this potential money maker that would perform like this as a standard. I could be wrong but I feel there is something wrong with the lens/AF.

I myself purchased the lens for mainly stills. I want better sharpness across the entire frame than the 16mm is giving me. I will test my lens with video footage as son as I get it and report my findings. If it is as bad as what you are seeing I will no doubt return it. Again, this puzzles me as Sony has just anounced they released dimensional info to allow third party lens manufacturers to start producing lenses for the E-mount.

One would think there is a lot to gain here by making a lens that performs well. There are getting to be a lot of NEX-5n's and NEX-7's out there with limited lens choices.


Mike
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Old Apr 11, 2012, 01:16 PM
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Quote:
Originally Posted by power View Post
Looks like you are getting AF motor noise Something is not right...IMO I don't think Sigma would release a lens on this potential money maker that would perform like this as a standard. I could be wrong but I feel there is something wrong with the lens/AF.
Thats my suspicion too. I kind of suspect the AF is broken in the camera and that the error is only visible with this lens. I am excited to hear what your experiences will be.

That said, I have done some testing without the autofocus as well and in this mode there are good news. I havent done any ithorough testing but the result regarding the sharpness so far is promising. It seems like the video is sharper in the whole censor, not only to the sides. For some strange reason the Sigma gives better autobalance too but I havent tested enough to state if this is a pattern or not.

But all in all, the lense isuseless for me if I cant find out what causes these issues.
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Old Apr 11, 2012, 01:40 PM
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Here is another video that shows how badly the autofocus works while video-recording. I am of course not planning to do close up aerial photo of my own hand, but it seems the camera/lens has the same issues for those far away shots as well.

Sigma 19mm autofocus-test (0 min 27 sec)
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Old Apr 11, 2012, 08:30 PM
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Well....I am just as unimpressed as you with the video focus I see the exact same thing as you. Jerky crap....The still samples I shot out my door at dusk pleased me with the sharpness. I need to take it up for a test flight and get some shots. If it is way above what my 16mm can produce I will keep it.


I did shoot an email off to Sigma explaining what we are seeing. It is a shame this autofocus is this poor. I am also going to call them tomorrow. I need to know exactly what they saw when they tested their product I mean really...did they think this was going to be acceptable even with a low end lens? C'mon guys!!!! I think they can do better than this. Sony did...

Ok, I am done until tomorrow....


Mike
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Old Apr 11, 2012, 08:38 PM
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too bad..... thanks guys for doing the work for the rest of us
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Old Apr 12, 2012, 02:29 AM
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Hi Power.
In a way I am glad you came to the same results, that at least means my camera is not broken. Still its sad though.

As you might be aware of, the Nex5n finds focus by measuring the contrast, not phase like some other cameras. This means the camera is dependent on some "focus-pumping" to find the correct focus. To a certain extent the stock pancake also do this but it handles it much more smoothly. The Sigma seems to go crazy sometimes. I have now done about 30 testvideos with the lens and the pattern is clear. Both nearfield and when shooting landscapes the pumping is very evident, sometimes its good of course, but most times not.

For me that get paid to do aerial filming I simply cant take the chance using a lens like this. Using manual focus is not an option, even at f8 its not possible to find a focus that will cover both near buildings and horizon. Therefore I am dependent on the autofocus. It has, as mentioned earlier, done a great job for me on earlier shootings with the pancake.

So. Today I will go back to the store I bought it and most probably I will return it. I will have a chat with them first though, because this particulary shop is regarded the best in Norway when it comes to cameras. Therefore there is qualified personel there that might have some answers.

Well, its a pity. I actually thought this lens would be the answer based on the reviews. Apparently the reviewers didnt go into depth with the lens using the film-option. I am looking forward to hear what you will find out Power. I will also definitly come back with all relevant information I can find. It still might be a better lens for you than for me. As much as I dont like the lens on the Nex5n as a film camera, I have noticed as the reviewers has found, that the lens is sharper than the pancake taking photos.
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Old Apr 12, 2012, 07:34 AM
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Very strange. I was very surprised that you made the statement that you were " even at f8 its not possible to find a focus that will cover both near buildings and horizon."
According to this depth of field calculator http://www.dyxum.com/lenses/dofCalc.asp

it should be possible even at F2.8 to have sharpness extend from 5metres to infinity with the 19mm lens so I am sure that shooting aerial video this would be acceptable as you would not be able to take in much building area at 5metres ? Just a thought.
I am interested in your tests as I also am disappointed with the Sony 16mm lens.
Ted (UK)
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Old Apr 12, 2012, 07:42 AM
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Sorry for your woes guys but I'd be interested to hear any thoughts on using this for stills. I'm certainly considering the 30mm Sigma prime as that's the setting I typically fly on the 18-55.

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Old Apr 12, 2012, 08:47 AM
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Quote:
Originally Posted by tedrobphoto View Post
Very strange. I was very surprised that you made the statement that you were " even at f8 its not possible to find a focus that will cover both near buildings and horizon."
According to this depth of field calculator http://www.dyxum.com/lenses/dofCalc.asp
To be honest I put a lot of effort into testing the autofocus, not so much the depth of field. I might have done a mistake when testing the manual focus but as far as I remember i used f8 and almost infinty focus and it did look blury. Therefore I would really appreciate if Power can test that. Use f8 and almost infinty focus to see if it is sharp enough overall to use for aerial. I cant do it myself because I delivered the lens back to the store today.


Quote:
Originally Posted by Lomcevac View Post
Sorry for your woes guys but I'd be interested to hear any thoughts on using this for stills. I'm certainly considering the 30mm Sigma prime as that's the setting I typically fly on the 18-55.
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I didnt do a lot of photos but among the few I took it was my clear impression that the lens was a lot sharper than the pancake. This is proabaly a safe lens to buy if your not into videoing and are planning to use the autofocus. The autofocus on photos work well.
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