Re: Sigma 18-35 F1.8 -Absolute Magic!
 

Hi Tom Van den,

Thank you for that video post. It may not have helped Noa, but I got some awesome information from it.

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

i believe the main reason some small sensor camera cam have same sensibility/noise as some large sensors is because large sensors as EA50 do not use all pixels, so you don't get the full benefit.

take a picture and record a video of the same scene. then resize the picture to 1920xXXXX. the picture will be much much better than the video. (and is not because of the compression)

a camera to fully use the 16mp and resize to full-hd size would consume much more power and generate a lot of heat. so they tho this.

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

In what way should it have helped me? Toms statement: "the samyang F1.4 becomes a F1.4 x 1.6 crop = F2.24 on my nex-ea50" is not correct at all, the cropfactor off his camera's sensor has no effect on the f-stop of whatever lens he adds onto his camera, that was all what I was saying, a samyang f1.4 or a sigma f1.4 on his camera will have the same sensitivity, the cropfactor does not change this. There is only one adapter that has a effect on the focal length and the f-stop and that is a speedbooster.

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

Hi Noa,

It was not a derogatory remark I just wanted to thank Tom for posting it. I'm new to he whole crop and full frame world and I'm learning a lot. My statement was to say, even though it did not answer Noa's question, i got a lot from the video. That's all bro...

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

the crop factor affects the depth of field and the light gathering "per-pixel", reflecting on the ISO performance.

the "F1.4 x 1.6 crop = F2.24" is applicable to the bokeh. want the same background blur? a f1.8 lens on crop factor will give similar results as a f2.8 on full-frame.

on the ISO side, a full-frame have usually a 1 stop better ISO performance, (ISO 3200 on full-frame looks like 1600 on crop). but as i mentioned, the fact the camera does not use all pixels for video capture, the result is not as expected.

of course, if you use an adapter as metabones speedboster, the full-frame vs. crop results will be almost the same, as concentrating the light on the smaller sensor "fixes" the focal length, add the extra stop of light, and gives the extra "missing" bokeh ;)

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

Just a small point here ... Sony cameras have a different size APSC sensor compared to Nikon (which is also the same as the Sony) Crop factor is in fact 1.5 not 1.6

I'm not going to argue here but my Nikon 28-75 F2.8 Full frame lens needs more light than my Nikon DX 17-50 F2.8 with both set at 35mm ... go figure ?

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

Noa,

thanks for correction. The video was misleading for me.
And Like Chris and someone else said. The nex-ea50 has many pixels and because of that it is putted on a big chip. Less sensitive unless you use a fast lens on it.

But the nex-ea50 will always gives a better depth of field (blurry background) than a normal sized sensor. (or much easier) That's the reason why I bought it.

But why can handle the aps-c sensor higher gains/iso? Because of the big sensor?

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

No problem :) I do know a bit about the technical side of videocamera's/lenses from shooting with different size sensors camera's and lenses but I didn't see any difference from using a full frame samyang lens compared to a MFT lens with the same f-stop when it comes to lightsensitivity when using both on the same camera. The cropfactor has a influence on the field of view and the bokeh so a 35mm will look much wider on a full frame camera then on a MFT camera and at the same f-stop the bokeh will be much more pronounced as well on the full frame camera.

Tom, is this comparison done at the same f-stops? My cx730 is also quite sensitive when the lens is wide open and at 24db and can keep up with my dslr up to almost 6400 iso at f2.8, but not at f1.4, then the difference becomes quite noticeable.

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

Noa,

the test in the video was the NEX-EA50 @ F1.4, iris full open, shutter 1/50 and my new hxr-nx3 @F1.6, itis full open and 1/50 shutter. So when both in auto the nx3 needed less gain! (yes I checked the settings and both were 1/50 and iris full open)

Like Chris said they put so many pixels in the nex-ea50 so it became less sensitive.
the nex-ea50 has 13,6 million pixels for video and the hxr-nx3 has 2,07million pixels for that.

But still not understand why the nex-ea50 can handles much higher gains without too much noise? @21db it is still decent the noise. I doubt my hxr-nx3 can handle that high gains.

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

These were on back order from July - November. They are just starting to ship again. Let me know if you need a Nikon or EF mount. We have both coming.

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

Except that, because a crop factor has a smaller sensor, and thus reads less light, if you wanted the same exposure settings, the same brightness to your image, you'd still have to factor the crop factor on your aperture or ISO.

All other things being equal, my 5d Mark ii at f/4 will be about the same amount of light on the metering as my 70D at f/2.8. Or I can set both their apertures the same ad up the ISO on my 70D.

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

but why can handle the nex-ea50 higher iso/gains without adding too much noise?
It's a APS-C sensor but with (too) many pixels on it -> pixels are smaller.

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

That was not my point, Tom thought the cropfactor applied to the aperture if you would use a full frame vs a non full frame lens on the same camera.

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

Doesn't it? To achieve all the same results between the two cameras (amount of light, DOF) you can't leave the aperture the same.

Re: Sigma 18-35 F1.8 -Absolute Magic!
 

No it doesn't, I said on the same camera. Tom thought that a full frame lens vs a non full frame lens on his camera would give him better low light performance if both where set at the same f-stop.