[ElJamoquio]

I have found the quality with a constant f4 aperture is better than variable aperture lenses -- even if they are faster than f4 on the wide end. I would buy the Pentax 17-70 f4 a lot quicker than I would the Sigma 17-70 f2.8-4 for that reason. But I am not familiar with the Nikon 24-85, so I can't really comment on that lens specifically.

Edit: I did look at Photozone's review of the 24-85 and it looks OK, but certainly not great. Some of the distortion is pretty fierce-some and borders certainly aren't strong unless stopped down quite a bit. Not a 16-50 killer in my book...

I've owned them both. I couldn't see a use for the 16-50 for me, so I concluded I just didn't like zooms.

If Pentax made a weather-sealed, sharp, stabilized (in body OK of course) $600 lens (really about $300 for me, bundled as a kit) as good as that Nikon it would make the decision a lot less obvious, that's for sure. The fact that the Nikon lens is less than half the price of the Pentax is silly, and illustrates the advantages of full-frame.

[cali92rs]

The fact that the Nikon lens is less than half the price of the Pentax is silly, and illustrates the advantages of full-frame.

Does it illustrate the advantage of full frame...or the fact that Pentax is charging ridiculous prices now because they consider themselves a boutique brand?

[Rondec]

I've owned them both. I couldn't see a use for the 16-50 for me, so I concluded I just didn't like zooms.

If Pentax made a weather-sealed, sharp, stabilized (in body OK of course) $600 lens (really about $300 for me, bundled as a kit) as good as that Nikon it would make the decision a lot less obvious, that's for sure. The fact that the Nikon lens is less than half the price of the Pentax is silly, and illustrates the advantages of full-frame.

But this is apples and oranges -- it would be like taking Leica lenses as proof of something. Pentax is expensive. The 16-50 is OK, but if you don't need the weather sealing (I do), you might just as well go ahead with a Sigma or Tamron for half the price.

On the other hand, the Nikon 17-55 f2.8 is 780 and looks like a better lens on APS-C than the 24-85 on FX. I would rather spend money and get sharpness without a ton of vignetting and distortion. The photozone review shows some pretty impressive distortion in some of its photos.

To better the Nikon 17-55 APS-C performance on a full frame camera, you really would need to go with a 24-70 f2.8, which is going to run you some serious change (~1800 dollars).

[ElJamoquio]

But this is apples and oranges -- it would be like taking Leica lenses as proof of something. Pentax is expensive. The 16-50 is OK, but if you don't need the weather sealing (I do), you might just as well go ahead with a Sigma or Tamron for half the price.

On the other hand, the Nikon 17-55 f2.8 is 780 and looks like a better lens on APS-C than the 24-85 on FX. I would rather spend money and get sharpness without a ton of vignetting and distortion. The photozone review shows some pretty impressive distortion in some of its photos.

To better the Nikon 17-55 APS-C performance on a full frame camera, you really would need to go with a 24-70 f2.8, which is going to run you some serious change (~1800 dollars).

There's plenty of easily correctable distortion.
There's plenty of easily correctable vignetting wide open.
There's plenty of extra sharpness over the APS-C lens too.
The lower cost, faster speed, extra wideness, extra length, etc is just a bonus.

The Tamron 28-75 is good and cheap. The Tamron 24-70 is better and more expensive. Wait, what cherry picking are we doing right now?\

How much is the Nikon D7100+Nikon 17-55? I don't really know. More than the D610+24-85? What are the comparisons on wideness, length, aperture speed, cost, weight?

[Rondec]

There's plenty of easily correctable distortion.
There's plenty of easily correctable vignetting wide open.
There's plenty of extra sharpness over the APS-C lens too.
The lower cost, faster speed, extra wideness, extra length, etc is just a bonus.

The Tamron 28-75 is good and cheap. The Tamron 24-70 is better and more expensive. Wait, what cherry picking are we doing right now?\

How much is the Nikon D7100+Nikon 17-55? I don't really know. More than the D610+24-85? What are the comparisons on wideness, length, aperture speed, cost, weight?

Have you used the 17-55 on a D7100, or are you speculating? The 17-55 has less measured vignetting and distortion across the focal lengths (the 24-85 has 3% at 24mm and 2.7% at 85mm).

If you are comparing prices, I think you should do it within a brand -- compare off brand to off brand, Nikon to Nikon, Canon to Canon, etc. It is the only way, as there is always some kind of premium that brand names command.

[ElJamoquio]

Have you used the 17-55 on a D7100, or are you speculating? The 17-55 has less measured vignetting and distortion across the focal lengths (the 24-85 has 3% at 24mm and 2.7% at 85mm).

If you are comparing prices, I think you should do it within a brand -- compare off brand to off brand, Nikon to Nikon, Canon to Canon, etc. It is the only way, as there is always some kind of premium that brand names command.

I've never used or even seen the 17-55. At that point in the memo I was comparing vs the 16-50.

Let me know what lens + camera comparison you'd think I'd be better off with and I'll compare. I agree we should compare within one brand.

So let's say we go with Canon. I can get by with an F/4ish zoom. I'll allow F/4.5 so that the APS-C models have a zoom to compete. What's better? Which costs more?
Let's go with Nikon. Which is better? Which costs more? Which has more range? Which has more width? Which is faster?

[jsherman999]

On the other hand, the Nikon 17-55 f2.8 is 780

$780, where? It looks like it's around $1200 (Adorama, B&H)

I went with a used $285 Tamron 28-75 f/2.8, and I don't think I'd every get better IQ from a zoom on aps-c than I get with that on 36MP FF. It doesn't have VR, though that rarely matters to me.

The point is though that something like a 24-85 variable lens on FF gets you generally better performance and equivalent speed to a much more expensive lens on aps-c - so the "I'm saving money by buying aps-c" doesn't always hold up after you start buying lenses, depending on your priorities.

[eyeswideshut]

You don't. I'd bet you $1 that every sentence of that post - even the questions - had a wrong statement in it.

Obviously

[Rondec]

$780, where? It looks like it's around $1200 (Adorama, B&H)

I went with a used $285 Tamron 28-75 f/2.8, and I don't think I'd every get better IQ from a zoom on aps-c than I get with that on 36MP FF. It doesn't have VR, though that rarely matters to me.

The point is though that something like a 24-85 variable lens on FF gets you generally better performance and equivalent speed to a much more expensive lens on aps-c - so the "I'm saving money by buying aps-c" doesn't always hold up after you start buying lenses, depending on your priorities.

Sorry. I'd looked at Amazon and the price that came up was apparently a used one.

The variable aperture zooms may be good, but they are a mixed bag. The only variable aperture zoom I own is the 55-300 which is OK, but certainly not on the same level as the Pentax 60-250 or 50-135. I own it because I wasn't willing to pay money for a constant aperture telephoto.

Honestly, the reviews don't look that great on the Nikon 24-85. Maybe it is great on full frame and would trounce other lenses on APS-C, but I doubt it. It looks to me like most 17-50-ish f2.8 zooms will have significantly better performance on APS-C than that lens. Even the DA 17-70 probably would outperform it, based on Photozone's testing.

[northcoastgreg]

There's plenty of extra sharpness over the APS-C lens too.

There's "plenty" of difference? What does that mean? If you printed at 300 dpi, how much larger a print could you make with Nikon's 24-85 FF kit zoom shot on the D610 compared to a print made with the DA* 16-50 on a K-3? Two inches larger? Four? Seven? I see large prints from FF cameras all the time. These are prints made from images shot, not with Nikon consumer grade glass, but with Canon L glass and Nikon nano-coated glass. The difference between these FF prints and the prints I can make from my K-5 and lenses like the FA 20-35 and the DA 17-70 are surprisingly minor. At medium print sizes (like 12" by 18") you can't tell the difference (in terms of resolution) at all, and even at larger print sizes, the difference is smaller than the numerical theorists might lead you to expect.

The little extra resolution you get from FF is nice, but what really makes for great prints, particularly landscapes, is microcontrast and color rendition. I don't find FF landscape shooters, whether I meet them locally are out in the field at various iconic locations in the western U.S., shooting with consumer grade glass on their FF cameras. They're shooting with Canon L glass or nano-coated Nikkors, usually zooms.

Pentax, with its limiteds and DA* glass, allows APS-C shooters to make images that exhibit comparable microcontrast and color rendition to high end Nikon and Canon glass. You give up a little resolution, but otherwise you're able to produce images which, optically speaking, have comparable impact.

The notion that somehow the Nikkor 24-85 is a "better" lens than the DA* 16-50 strikes me as an example of mis-aligned priorities. I've seen stunning images taken the DA* 16-50 -- images with plenty of microcontrast, bite, and rich, vibrant outstanding color. I've seen no such images from the Nikkor 24-85. It's merely a very nice consumer grade lens, but hardly in the same league as high-end Canon, Nikon, Pentax, or Olympus glass. The fact that one can squeeze a bit more resolution out of that lens than one can from hi-end Pentax glass shot on APS-C cameras or high-end Olympus glass shot on m43 leaves me cold. Nowadays almost any lens/camera combination can provide more than enough resolution for the needs of most photographers. So the fact that one combination provides a little more rez is largely insignificant.

[ElJamoquio]

There's "plenty" of difference? What does that mean? If you printed at 300 dpi, how much larger a print could you make with Nikon's 24-85 FF kit zoom shot on the D610 compared to a print made with the DA* 16-50 on a K-3?

20% larger than the D7100 + 17/55!! (I'm only allowed to compare Nikons to Nikons) Not a bad deal for the same price equipment out of the box. I bought mine for $400 less but whatever, they're the same price right now.

Plus my future lenses are so much cheaper.

That's why I'm here in the Pentax FF forum, arguing that Pentax should make FF. People keep asking me "why are you here, in the full frame forum, when I don't care if Pentax makes a full frame"?

[Pål Jensen]

Equivalence is nonsense because no one buy or use cameras of different formats in order for them to be equal. They use their camera to their best advantage. No one will deliberately increase noise on a larger format cameras in order for it to mimick a smaller format if they can avoid it. At least if they are photographers.
And theres no difference between film and digital in this respect; increasing ISO on your DSLR is equivalent to using a higher speed film in you film camera. Due to the fact that "Equivalence" (the DOF wide open kind) has no relevance for people who actually take photographs, there is no demand for 6400ISO 4X5 sheet film! Nor has there been any demand for Pentax 6X7 zoom lens with max aperture of F:11 in order to be equivalent to kit zoom lens for 35mm.

Photography is about the physics of exposure. Without exposure you get no photograph. If you do not use this physics as basis for understanding you get irrelevant resuts and that make some people very confused; so confused that they think there are misleading lies printed on their lenses!.
If you look at the physics of exposure you will see thats theres no equivalency apart from equivalent exposure. That all other parametres including DOF is totally subjective and hence unsuitable as criteria for general comparisons.
Not only is DOF subjective but the DOF range of various formats with "usual" lenses is equally subjective; there are no objective reasons to compare anything to the 35mm (FF) format nor are there any objective reason for the the DOF range you get from a typical FF system is even desirable. It is all subjective.





---------- Post added 05-31-14 at 03:45 AM ----------

Let's get the facts straight: lens manufacturers were accused of lying by putting the real focal length and aperture values on their lenses, but none of them can sell a lens with the oh-so-much-better "equivalence" system because the system falls apart as soon as you put that lens on a camera with a different sensor size.

In addition, it falls apart cause it can't be used to anything meaningful regarding exposure. A 2.8 lens is a 2.8 lens regardless of format or DOF as it gives the same expoure at the same sensitivity. And you NEED to keep those parametres constant for equivalency and thats what lens makers do. DOF has no more meaning as measure for equivalence than anything else taken in isolation.


---------- Post added 05-31-14 at 03:51 AM ----------

Well, you might want to watch the video, because I do explain the physics. If you disagree with my math, just let me know where my math is wrong and I'll happily fix it.

Re: my usage of bokeh, it seems like everyone knew what I meant. I'm aware of the technical definition of bokeh, but I'm also aware of how people commonly use it as jargon to mean the amount of background blur. Saying, "Small sensors have less bokeh" (as a myth) was more concise than saying, "Small sensors are less able to create a shallow depth of field."

Whats written on lenses; Ie focal lenght and aperture is physics and not lies. They are not misleading in anyway. And if you think it is misleading it is because you don't understand it. BTW Focal lenght is independend on format. Your last sentence is utter nonsense.

[ElJamoquio]

If they were using focal length on their lenses you'd have a point, but the manufacturers aren't.

[Kunzite]

Manufacturers aren't... what? They are marking their interchangeable lens with the focal length (or not marking them, in the case of Pentax Q).
Are you cherry picking an irrelevant example - the compacts - and attempt to apply it over the entire industry?

Not only is DOF subjective but the DOF range of various formats with "usual" lenses is equally subjective; there are no objective reasons to compare anything to the 35mm (FF) format nor are there any objective reason for the the DOF range you get from a typical FF system is even desirable. It is all subjective.

Except if you want to "prove" the "superiority" of one format, like ElJamoquio here.

[Rondec]

20% larger than the D7100 + 17/55!! (I'm only allowed to compare Nikons to Nikons) Not a bad deal for the same price equipment out of the box. I bought mine for $400 less but whatever, they're the same price right now.

Plus my future lenses are so much cheaper.

That's why I'm here in the Pentax FF forum, arguing that Pentax should make FF. People keep asking me "why are you here, in the full frame forum, when I don't care if Pentax makes a full frame"?

I don't know that I buy this 20 percent increase. Sounds like a made up statistic to me. But how big are you printing/viewing right now? I don't really think you can get much increase over the K3. You biggest increase would come from combining multiple shots in a panorama.

I should mention that if Pentax releases a full frame camera, I will probably get it. I just won't get it (a) because equivalence proves it is better or (b) because it will be cheaper.