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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

New Sigma 18-35mm f/1.8

All what Patrick said. People should give up multiplying focal lenghts by crop-factors. It's just confusing everyone. I don't know how many times i have explained, or tried to explain, that the focal length is the same, regardless if the lens is mounted on a APS-C or FF-body. ;)

Patrick, i look forward to hear from your Dragon-tests. Can you post some 6k-images?
...and i guess i have to test AF-performance again, thanks for noting that.

This lens is awesome, period. I think everyone should have it and sigma needs to re-do the 8-16 for their art-line, besides other lenses. :)
 
Oh yes. Let sigma have a go at the 10-18 range my tokina is nowhere close to the sharpness the 18-35 produces. Maybe I didn't catch an awfully good one but still.
And then let's do it at FF :)

Maik, if everything works out I might have some to share. I just hope I can find the time to shoot some nice stuff. Won't have the camera for too long if at all but I'm counting on it at the moment. Will probably mostly be landscape stuff. Not a lot of skin if at all because it will be shown to the public. Maybe I should hire a model. Ah damn money...

Edit: too bad I can't use the sigma @ 6K
 
Patrick Grossien said:
Oh yes. Let sigma have a go at the 10-18 range my tokina is nowhere close to the sharpness the 18-35 produces. Maybe I didn't catch an awfully good one but still.
And then let's do it at FF :)
Click to expand...
Oh yeah, thats the only thing on the 18-35 that bugs me from time to time.

Maik, if everything works out I might have some to share. I just hope I can find the time to shoot some nice stuff. Won't have the camera for too long if at all but I'm counting on it at the moment. Will probably mostly be landscape stuff. Not a lot of skin if at all because it will be shown to the public. Maybe I should hire a model. Ah damn money...
Click to expand...
Hehe, it doesn't have to be always a hot model, but yeah, it helps when it comes to lens testing. Skin tones are important. ;)

Edit: too bad I can't use the sigma @ 6K
Click to expand...
Danm... Not even 6kHD or 6kWS? Did you test multiple focal lenghts/apertures?
How much does it cover? Maybe 5.5k? We will probably get custom resolutions with a future firmware upgrade.
 
Jeff Kilgroe had an interesting post in 2012
http://www.reduser.net/forum/showth...11-16-Coverage&p=947226&viewfull=1#post947226

The last line says "* ANGLE OF VIEW (AOV) IS THE VALUE THAT REALLY MATTERS. You need to know what AOV is achieved by which focal length on your intended imager size."

So, what I'm really interested in finding is (I must be dense, as I don't have the clear answer in my mind yet):

for 4K HD with the Scarlet, and at whatever the highest image size I could get without vignetting on the Dragon, will the AOV of the Sigma 18-35 be larger than the AOV I'm currently getting on my Canon 24-70 II - and what exactly is that AOV range?

This would be very useful to add to RED's Cinephotography tools http://www.red.com/tools/crop-factor.
 
Yeah, I dunno, I use the multiplying of crop factor to get a rough idea of FOV (...or AOV?) The generally accepted idea is that the bigger the sensor, the shallower the DoF, but the truth is it's the opposite. HOWEVER, you need to go to a wider lens to get the same FOV on a smaller sensor, and in doing so the DoF increases substantially. I tried explaining this to an AC one time and they just kept pointing to their DoF calculator's calculation saying bigger sensor means deeper DoF... I almost wanted to crack out a 5D to see how quickly they'd change their tune pulling focus at t2 on it.

When s35 was essentially the only game in town it made sense (sort of), but with sensors now being FF35/~65mm/1.0x and ~APS-H/1.3x compared to APS-C/s35/1.6x and m43/s16/2.5x, there seems to be a logic gap in a lot of people's working understanding. 25mm on FF35 has an equivalent FOV of ~16mm on s35... 16mm has a way deeper DoF. In other words, as the sensor sizes change moving forward (RED's a perfect example, first s35/4k, then APS-H 5k MX, now 1.2x with 6k Dragon), if not using crop-factor multiplication, how else are you going to judge which lens to use for equivalent wide, med, long FOVs?
 
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Les, a lot of people get confused about this. When you're talking focal lengths, Milimeters are absolute. It doesn't matter at all what format (sensor size) the lens is desired for. When you set the Sigma Zoom at 24mm, you will get the same frame that you would get from your Canon zoom set at 24mm. So, overall, the Sigma will give you wider images than the Canon 24-70. I should compare the Sigma to my Canon 17-40.
 
Christopher Barrett said:
Les, a lot of people get confused about this. When you're talking focal lengths, Milimeters are absolute. It doesn't matter at all what format (sensor size) the lens is desired for. When you set the Sigma Zoom at 24mm, you will get the same frame that you would get from your Canon zoom set at 24mm. So, overall, the Sigma will give you wider images than the Canon 24-70. I should compare the Sigma to my Canon 17-40.
Click to expand...

What he said. A 24mm is a 24mm is a 24mm.
 
Nick Morrison said:
What he said. A 24mm is a 24mm is a 24mm.
Click to expand...
And the SiGMA is a true 18-35mm, and, of course, wider than the Canon 24-70.

@Mike P., as long as you understand what you are calculating there, it's perfectly fine to do it. ;) FOV/AOV is the key here. But people tend to forget about the other characteristics, like you said, DOF and the overall look of a lens. Those discussions always start with something like "it's a 24, but on a crop-sensor it's becoming something like a 35mm". I can't hold back in such moments. ;)
 
Maik Müller said:
And the SiGMA is a true 18-35mm, and, of course, wider than the Canon 24-70.

@Mike P., as long as you understand what you are calculating there, it's perfectly fine to do it. ;) FOV/AOV is the key here. But people tend to forget about the other characteristics, like you said, DOF and the overall look of a lens. Those discussions always start with something like "it's a 24, but on a crop-sensor it's becoming something like a 35mm". I can't hold back in such moments. ;)
Click to expand...

Right. The whole shallow depth of field crop factor discussion can be an endless catch 22 discussion that has no end. But I will say one thing. I find that how sensor size affects FOCUS DISTANCE is the biggest factor for me. Here's what I mean.

I have a 50mm on a Scarlet. To get a nice portrait close up, I stand 5 feet away.
Put that 50mm on a 5D and suddenly its much WIDER. So I walk in 2 feet to get a matching closeup to the Scarlet. But because I'm now 3 feet away, the FALL OFF is much greater, and the background is much more shallow (ie the subject is much closer to lens than on Scarlet, while the background is still far off in distance).

Its because bigger sensors tend to make us work CLOSER that affects shallowness. If you don't get any closer to subject, then you don't notice the shallowness..only the wider field of view.

Anyway. That's my 2 cents. Ultimately, crop factors are a MATHEMATICAL issue and up to little debate, but how we each chose to understand it is purely subjective, so to each their own!
 
Yeah, but try telling that to someone relying solely on a dof calculator and not what they're seeing. For all practical purposes, the bigger the sensor, the more shallow the DoF plane gets (whether you march in the camera or use a longer lens to compensate for the FOV difference.)

Slightly more on topic; does the 18-35 cover FF6k at any focal lengths? Particularly 24mm+ (anything under that would be a bonus)? I mean, if it covers FF6k from 24 onward that's still a lot of lens in one package. T1.8 constant makes it very special. Hell, there aren't that many/any affordable 18mm t1.8 out there. The closest thing is a RPP, and even that is $3k+ used (and it weighs a ton, and is huge, and also doesn't cover 6k)

Oh, and for whoever asked on the last page -- Dragon 5k is smaller than MX 5k... (slightly bigger than MX 4k though).

Also, Allstar just announced their rehoused PL version for $2950 (no focus through increase unfortunately)... Time for another group buy, maybe?
 
Isn't GL Optics option better than allstar? You can get interchangeable mounts, it's para focal, and 300 degree. How does Allstar compare?
 
Allstar's is getting "released" at NAB, so I don't know (he said he'll be showing it off at the show). But generally speaking, I think their track record is fairly good... I think the parfocality(?) is based off the original lens, not added in during the rehouse. And yeah, I doubt Allstar will have changeable mounts, since the A-mount conversions are based off PL.
 
The original lens is not para focal, the GL Optics rehouse is apparently
 
Nick Morrison said:
I have a 50mm on a Scarlet. To get a nice portrait close up, I stand 5 feet away.
Put that 50mm on a 5D and suddenly its much WIDER. So I walk in 2 feet to get a matching closeup to the Scarlet. But because I'm now 3 feet away
Click to expand...

One thing to be really mindful of though, is that even though you are matching composition by moving forward, you are dramatically changing your perspective and the way the subject's face will be rendered is entirely different.
 
Christopher Barrett said:
One thing to be really mindful of though, is that even though you are matching composition by moving forward, you are dramatically changing your perspective and the way the subject's face will be rendered is entirely different.
Click to expand...

Yes many forget that the characteristics of the lens don't change because of FOV. Shooting faces close up with wide lens is not going make you many friends!
 
Bob Gundu said:
Yes many forget that the characteristics of the lens don't change because of FOV. Shooting faces close up with wide lens is not going make you many friends!
Click to expand...

Right, but when you are on full frame, long lenses become "wider" so you end up either getting closer (not putting on a wider lens), or throwing on a longer lens, which either way...gets you more shallow. But yes...when you get closer, the relationship btw foreground and background does change, and needs to be taken into consideration (ie could "feel" different).
 
Maik Müller said:
Oh yeah, thats the only thing on the 18-35 that bugs me from time to time.


Hehe, it doesn't have to be always a hot model, but yeah, it helps when it comes to lens testing. Skin tones are important. ;)


Danm... Not even 6kHD or 6kWS? Did you test multiple focal lenghts/apertures?
How much does it cover? Maybe 5.5k? We will probably get custom resolutions with a future firmware upgrade.
Click to expand...

Maik, I'll mount the lens and see for myself. I think I remember that the lens covers 6K from mid range. I just don't know yet. What I should have said is : too bad it's not covering fully. :) if it only covers at around 35, the zoom doesn't make much sense any more. But if I'll be able to own a 6K dragon that will still be some time away so it doesn't matter too much yet :) I'll keep you updated.
 
Les, the whole comparison situation is just what you make of it. It just depends on where you come from.
As a full frame DSLR shooter you should know which focal length you use for which application with a FF35 sensor. Now if you use those lenses on a different sensor/camera you might want to know what you can compare the length to. If you started off with cinema you have S35 as a reference. That's why you can change the reference frame size in the RED online tool.
 
Les C. said:
Jeff Kilgroe had an interesting post in 2012
http://www.reduser.net/forum/showth...11-16-Coverage&p=947226&viewfull=1#post947226

The last line says "* ANGLE OF VIEW (AOV) IS THE VALUE THAT REALLY MATTERS. You need to know what AOV is achieved by which focal length on your intended imager size."

So, what I'm really interested in finding is (I must be dense, as I don't have the clear answer in my mind yet):

for 4K HD with the Scarlet, and at whatever the highest image size I could get without vignetting on the Dragon, will the AOV of the Sigma 18-35 be larger than the AOV I'm currently getting on my Canon 24-70 II - and what exactly is that AOV range?

This would be very useful to add to RED's Cinephotography tools http://www.red.com/tools/crop-factor.
Click to expand...

Maybe this helps:

24mm with the Sigma is EXACTLY the same as the 24mm of the Canon when both are used on a RED DSMC camera. The rest of course is about lens quality (sharpness, CA, etc.)

The only thing you need to know in order to see if the Sigma "works" is where it vignettes. And the sigma doesn't vignette at 4K at all. For Dragon you would have to search the forum. Or maybe even this thread. I read somewhere how it vignettes. Or wait till I test it out. If I can find the time, I'll do a quick vignette test.
 
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