[Mirton]

My niece turns 5 this Sunday and i was prepping up for her b-day party as the family's designated photographer. I was going through my primes deciding what to carry in my bag, the Rokinon 35mm f1.4 UMC or the Sigma EX 30mm f1.4. I also was comparing my SMC Pentax-F 50mm f1.4 vs the Sigma EX HSM 85mm f1.4. I took some pictures of my cat in similar circumstances with similar ISO and aperture with no WB adjustment lightly adjusting the levels. I took some quick pictures with each one to get a feel of their aesthetic rendering qualities.

Rokinon vs. Sigma
I think the Rokinon 35mm f1.4 UMC is an excellent lens (although manual focus), with superior contrast (and better coating than the Sigma EX, no wonder it compares favorably to the Distagon 35mm f1.4) It also almost a full stop brighter. (77mm front thread, FF vs 62mm DC of the sigma)

Rokinon 35mm f1.4: https://www.flickr.com/photos/22728984@N04/14311278521/in/photostream/
Sigma EX DC 35mm f1.4: https://www.flickr.com/photos/22728984@N04/14311278401/in/photostream/

Pentax vs. Sigma
I thought the Pentax F 50mmm f1.4 performs strongly with slightly higher contrast, better colors. The Sigma 85mm f1.4 has better isolation (bokeh) but i'm not a big fan the way it renders colors overall.

Pentax F 50mm f1.4: https://www.flickr.com/photos/22728984@N04/14311278181/in/photostream/
Sigma EX 85mm f1.4: https://www.flickr.com/photos/22728984@N04/14128089617/in/photostream/


Note: I realized later on that my Rokinon was shot wide open and not at f3.5. The aperture lever was stuck and needed some attention. That means that there's no differences in transmittance between the lenses as i had previously pondered.

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Last edited by Mirton; 05-31-2014 at 06:04 PM.

[Giklab]

Use the Sigma, since it has AF. I suggest not using the filter thread as a guide to maximum aperture . On the same camera, the Sigma and the Rokinon send the same amount of light to the sensor (within 20% difference).

[theraven871]

Use the Sigma, since it has AF. I suggest not using the filter thread as a guide to maximum aperture . On the same camera, the Sigma and the Rokinon send the same amount of light to the sensor (within 20% difference).

I agree, use the sigma.
Auto focus is such an important feature these days.
I've lost great photos from having to manually focus as fast as I could and being slightly off.

These days, most things are recoverable or fixable in simple PP (such as Lightroom).
You can correct colors, exposure, lens distortion, Chromatic Aberrations, Noise, Detail etc etc.
But you can almost never correct an out of focus exposure.

[Mirton]

I ended up taking the Sigma EX 30mm f1.4, and the Tokina 280 AT-X 28-80mm f2.8. The sigma proved extremely useful when taking pictures inside the dark bouncing castle where the children congregated. Thank you for all of you input.