Full Frame 50mm BOKEH and Distortion example added.

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lukewoodford

FYI, I am Luke Woodford.....by Luke Woodford
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So i took my new D700 and Sigma 50mm 1.4 on an outing the other day. Two things I noticed (bare in mind I dont know too much on the technical side).

1- I noticed wonky edges on the outside of a few images. I got this on my D300 at about 24mm I suppose although I never worked it out exactly. I didnt think I would get this on 50mm full frame as its not a wide angle. Is this normal?

2- Also quite an annoying thing I noticed is that I have to get closer to get good bokeh which is quite annoying. I suppose getting an 85mm would correct this but still annoying. I suppose its just getting used to the camera.
 
the nicer bokeh is down to the distance to subject relationship, closing the distance renders more out of focus background to give a nice creamy/dreamy backdrop. The downside is some distortion in getting closer.. which is why i would personally use 85mm+
 
Ok ill post an example, give me a couple mins.

Ok here it is. I hope you get the idea. Its right in the middle but wonky on the outside (the verticles). Maybe im on the wrong settings or something?

homeless2033.jpg
 
It is definitely exhibiting barrel distortion, what model was the lens. mind you not being a nikon user i wouldn't know if that model is known for it anyhow.

P.s Did you take a picture of a drunk guy wetting himself???:nono:
 
onform said:
It is definitely exhibiting barrel distortion, what model was the lens. mind you not being a nikon user i wouldn't know if that model is known for it anyhow.

P.s Did you take a picture of a drunk guy wetting himself???:nono:
Click to expand...

Its the new sigma 50mm 1.4. Id like to know if this is normal or if I should do something about it?

And yes I did, im trying to do homeless street people at the moment. Im suprised you noticed though, it looks like a drink just spilled over.
 
TBH the Sigma 50mm is awesome, but I would use it for this sort of shot (taken about an hour ago), rather than for broad daylight shots.

Zero light (only light was from the furnace), wide open.


3167214924_c7c9dc90de_o.jpg

​

Can't say I've really noticed distortion, but I can't say I've looked for it.

I'll have a quick look and see if I can find any in my shots...
 
Take a photo of a bricked wall straight on, if you want to get a better idea of how bad it is.
 
puddleduck said:
TBH the Sigma 50mm is awesome, but I would use it for this sort of shot (taken about an hour ago), rather than for broad daylight shots.

Zero light (only light was from the furnace), wide open.


3167214924_c7c9dc90de_o.jpg

​

Can't say I've really noticed distortion, but I can't say I've looked for it.

I'll have a quick look and see if I can find any in my shots...
Click to expand...


That would be very appreciated if you could. I love the lens, its super sharp wide open and deadly silent, just wanted to know if this was a normal thing with 50mm lenses on full frame, because if it is it doesnt make much sense to me.
 
Liam said:
Take a photo of a bricked wall straight on, if you want to get a better idea of how bad it is.
Click to expand...

+1 then you will tell just how bad it is.

The review on the canon mount version doesn't look to bad distortion wise

but to be honest as puddleduck mentioned the lens was never really designed for this type of shooting..
 
I hardly have any shots with straight lines in it, I tend to use the lens close up and wide open.

The nearest shot I have it this (street shot, wide open again)


DSC_2056-web.jpg

​

The lines look pretty staight to me, maybe some barrelling top left, but I may have been titled a bit - seems fine to me tbh.
 
puddleduck said:
I hardly have any shots with straight lines in it, I tend to use the lens close up and wide open.

The nearest shot I have it this (street shot, wide open again)


DSC_2056-web.jpg

​

The lines look pretty staight to me, maybe some barrelling top left, but I may have been titled a bit - seems fine to me tbh.
Click to expand...

Does this mean I have a bad copy? Or could it be D700? Or normal in the pic i posted?
 
I think your lens is fine, you are tilted a little bit, so your verticals are natually not straight.

TBH I can't really see much wrong with your shot distortion wise..?

I suppose you can shoot a brickwall, but personally I would just enjoy your lens and not worry about it :)
 
Barrel Distortion ? Is that like saying a 17mm lens isn't straight on a crop?

50mm is not that wide so if you take photos of anything, like a brick wall, and if you are close enough, the lines will not be straight, that's just physics.

There is a reason why on FF, 85mm to 135mm is considered the preferred focal length, 50mm is a bit too short.
 
On 35mm, barrel distortion is likely in f/1.4 50's, not so much in the f/1.8 50's.
I guess its a trade off for the extra speed, the Nikon version has barrel distortion on full frame too.
 
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