[pentaxk10duser]

Thanks Paul I missed that Thank you .Worst part I must have listen to this video ten time .

[Mock]

In this video the guy talks about how sigma can change the mount to fit different cameras so why can't you buy one for nikon and get then to put on the pentax mount like they say can be done. That way if for some reason the pentax version does not have the sr built in and your still paying the same price as one that does , (because sigma said it cost them more to produce pentax mount lens because they don't sell as many) My guess the pentax version will have to have the sr built into this lens if they are saying the mount can be changed to fit different camera body's.Sigma 18-35mm f1.8 Review - a GROUNDBREAKING Lens! - DigiDIRECT TV Ep 036 - YouTube. If this is the case and you can change mounts then why can't you order a lens for a pentax mount right now.

Another thing to point out, since I keep seeing this misconception: Sigma's mount conversion service is only available when the lens has already been released in that mount. It is not a sneaky back-door way to get new Sigma glass in Pentax mount.

[ElJamoquio]

Damn it! Foiled again!

[HAHA]

In this video the guy talks about how sigma can change the mount to fit different cameras ...
.Sigma 18-35mm f1.8 Review - a GROUNDBREAKING Lens! - DigiDIRECT TV Ep 036 - YouTube. ...
.

Check 9:15 into the video...
Do you notice that the 120-300 F2.8 is listed as a qualifying lense for Pentax ?

[Zygonyx]

That IS groundbreaking news, if not a mistake !

[ElJamoquio]

It's been a mistake a few times. Never seen in the wild.

[bossa]

Meh.

The reality is that the F/2.8 zooms in Nikon are better than the slower lenses, by and large, even when stopped down.

Personally it'd be tough for me to justify both. Right now I have a 24-85 F/3.5-4.5 and I'm thinking I'll keep that and put the 14-24 f/2.8 under that. The Nikon 14-24 weighs twice as much as the Sigma 8-16 (Pentax) that I have but that Sigma leaves some IQ to be desired. The Sigma FF 12-24 is actually not incredibly good either. I'd really like a 12mm (or 8mm on APS-C). I feel like I'm compromising already at 14mm; 16mm is out of the question.... so it's the 14-24mm or nothing.

Would I prefer a 12-24 F/4? Sure, but it doesn't exist. At least the 14-24 should be fun for some astro stuff.

I have the Nikon 14-24 and it's awesome. I also have the Tamron 24-70, which I thought was far better than the Nikon 24-70 I tested - The Tammy being not so great at 70mm though.

I am finding that my DA*200 is better than my Nikon 70-200 VRII at 200mm. I used both to shoot the lunar eclipse a few weeks ago and it was a no contest. I found myself wishing I still had my FA*300 F4.5.

A few weeks ago I tried Sandy Hancock's DA*300 on his K-3 and felt that it beat my AF-S 300/TC 1.4X combo easily.

My thinking these days:
1: APS-C for macro & Telephoto
2: F1.8 is faster than F2.8 (don't care about the DOF here) and that an f/1.8 lens will allow one stop lower ISO for controlling noise OR a faster shutter speed for the same ISO to control motion. They all have their uses, depending upon your needs.
3: I wish I still had my 60-250
4: I love the size of my FA 77LTD and wish all of my lenses had the same elegance and size. The Sigma 85 is great but it's a monster on a D800e with a battery pack. Carrying Nikon gear and a bag of lenses is a vastly different experience physically to my old Pentax kit and to be honest I reckon I took better pictures with the latter.

[ElJamoquio]

2: F1.8 is faster than F2.8 (don't care about the DOF here) and that an f/1.8 lens will allow one stop lower ISO for controlling noise OR a faster shutter speed for the same ISO to control motion. They all have their uses, depending upon your needs.

F/1.8 on APS-C is exactly as capable as F/2.8 on FF. Same DOF range, same SNR range. So it's really a straight comparison.

The F/2.8 zooms are generally wider and longer than the F/1.8. I guess the one exception is the olderish Tamron 28-75 that is no wider, but is still longer.

[Edgar_in_Indy]

F/1.8 on APS-C is exactly as capable as F/2.8 on FF. Same DOF range, same SNR range. So it's really a straight comparison.

He specifically said he doesn't care about the DOF. So the f1.8 gains him the advantage of faster shutter speed and/or lower ISO. And when you mention SNR, wouldn't that refer to the sensor?

[ElJamoquio]

It's the same snr. No better, no worse. The iso readout on the ff says a higher number but it allnworks out to be the same (because of equivalence! )

[Mock]

It's the same snr. No better, no worse. The iso readout on the ff says a higher number but it allnworks out to be the same (because of equivalence! )

This only serves to confuse people, assuming all else is equal (framing, DOF, etc.), an ISO 100 shot out of a APS-C camera compared to the same out of a FF would be indistinguishable to 99% of us. The fact is, in a situation where an f/2.8 lens will shoot at 1/30s, the f/1.8 will go at 1/80s - a significant advantage.

[Quicksand]

For a concept that is supposed to simplify understanding, "equivalence" sure seems to tie a lot of people into knots.

The fact is, in a situation where an f/2.8 lens will shoot at 1/30s, the f/1.8 will go at 1/80s - a significant advantage.

Sure, if you keep ISO the same on both APS-C and FF, that's true. But then your output isn't really equivalent. FF will have a noise advantage and shutter speed disadvantage.

If you want a truly equivalent shot -- FOV/framing the same, DOF the same, noise comparable (assuming similar sensor technology), you need to crank the ISO on the FF camera. And that ends up evening out the shutter speed.

[ElJamoquio]

This only serves to confuse people, assuming all else is equal (framing, DOF, etc.), an ISO 100 shot out of a APS-C camera compared to the same out of a FF would be indistinguishable to 99% of us. The fact is, in a situation where an f/2.8 lens will shoot at 1/30s, the f/1.8 will go at 1/80s - a significant advantage.

People are indeed quite confused. But your advantage is incorrect. APS-C has no advantage in shutter speed or noise at a given DOF - they're the same.

All else being equal, an F/1.8 -> F16 lens on APS-C will give exactly the same DOF with exactly the same noise with exactly the same shutter speed as a F/2.8-F22 lens on FF.

The differences will be only in the exif, in terms of reported ISO and reported aperture.

So life is easy, and we can choose based on cost, weight, focal range, and other factors.

[Mock]

For a concept that is supposed to simplify understanding, "equivalence" sure seems to tie a lot of people into knots.



Sure, if you keep ISO the same on both APS-C and FF, that's true. But then your output isn't really equivalent. FF will have a noise advantage and shutter speed disadvantage.

If you want a truly equivalent shot -- FOV/framing the same, DOF the same, noise comparable (assuming similar sensor technology), you need to crank the ISO on the FF camera. And that ends up evening out the shutter speed.

I'm not tied into a knot, I understand it quite well. I acknowledge that ISO 100 from both camera isn't totally equivalent. I'm arguing that the average photographer looking at the two shots won't be able to tell a difference in the IQ of the image at ISO 100. However, if there is a person walking through the frame, only one of those images (1/30s vs 1/80s) is going to be sharp.

I'm not into discussing a DxO level of sensor geekery, I care about the finished result. In my opinion, if we're comparing APS-C and FF, the noise output is functionally equivalent at base ISO.

If we're comparing FF and a 1 inch or smaller sensor, then there becomes an appreciable difference.

[ElJamoquio]

I'm not tied into a knot, I understand it quite well. I acknowledge that ISO 100 from both camera isn't TOTALLY equivalent. I'm arguing that the average photographer looking at the two shots won't be able to tell a difference in the IQ of the image at ISO 100. However, if there is a person walking through the frame, only one of those images (1/30s vs 1/80s) is going to be sharp.

I'm not into discussing a DxO level of sensor geekery, I care about the finished result. In my opinion, if we're comparing APS-C and FF, the noise output is functionally equivalent at base ISO.

If we're comparing FF and a 1 inch or smaller sensor, then there becomes an appreciable difference.

Functionally equivalent? Maybe. But at 'equivalent-equivalent', the noise is exactly the same.



Dr. Camera