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11-08-2010, 09:00 PM   #1
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Is f2.4 the new f1.8?

I know, doesn't make any sense. But here's what I mean: I kind of have it in my head that anything above f2.0 is going to hinder my ability to shoot in low light. This comes from years of not being able to shoot above 1600 without significant noise. Now the K-5 comes along, and I'm seeing people claim that 12800 is usable, and 6400 is very good.

I just noticed that the 35/2.4 came out, and my initial response was "too slow". But after thinking about it for a second, it seems that with the K-5 it would be plenty fast. Presuming I can safely go up to 6400 or even 12800, f2.4 at those apertures would let in the same amount of light as f1.8 at 1600 or 3200.

Of course the bokeh is different, etc. But the new sensors is changing how I think about lenses.

11-08-2010, 09:06 PM   #2
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Sure, you now don't need as fast glass if you don't care about DOF. But a lot of people get the fast lenses for the thin DOF, not ust the enhanced low light ability. I think companies will still make fast lenses as long as people will still buy them.
11-08-2010, 09:08 PM   #3
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Yes, that's true. And of course that's another reason why full-frame is the holy grail for many. I used to have a Canon 5D and the DOF with an f1.4 lens on that was incredible.
11-08-2010, 09:27 PM   #4
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Don't forget that the max aperture of a lens also affects AF performance. A F2.4 lens is just under one stop slower than a F1.8 lens, so you're going to have almost half as much light hitting the AF module, something that hi-ISO can't do anything about.

11-08-2010, 09:33 PM   #5
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Typically I only buy fast glass and F/1.4 is what I am looking for for glass under 100mm. That said I pretty much shoot at f/2.0-f/4.0. If the lens has excellent optical qualities at f/2.4 then I don't have a problem with it. I will probably buy the DA 70mm, but it will be the slowest prime I own for either Canon or Pentax bodies.
11-08-2010, 09:34 PM   #6
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At 35mm you can go to f/1.4 even manual focusing. Which is essential if you are shooting night.
Moreover there is a plethora of cameras with comparable low light capabilities (k-x, k-r, d5000 etc.) that easily shoot at 50mm f/1.4.
However good high Iso capabilities become, they always greatly reduce IQ. So base Iso is preferable.
IMO f/2.4 is a fast aperture for NORMAL shooting conditions. Not low light shooting.
11-08-2010, 09:35 PM   #7
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Yes, max. aperture size does matter...

But it doesn't mean that the 35/2.4 is an ordinary lens. It's excellent, and small, and not badly built for an all-plastic lens, and within the budget for most people - ticks the right boxes for newbies and early prime enthusiasts.
11-08-2010, 10:14 PM   #8
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Brighter viewfinder, thinner DOF - that's what I care for.

11-08-2010, 10:37 PM   #9
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QuoteOriginally posted by climit Quote
However good high Iso capabilities become, they always greatly reduce IQ. So base Iso is preferable.
Well said. High ISO is and always will be a trade off, no matter how much Pentax tries to make it the new pissing contest after megapixels.

ISO is only one small part of the equation, and has anyone stopped to wonder what an also-ran the K-5 might be otherwise?

Also high ISO, grain/noise, happens to be an valid artistic factor available to the photographer to exploit, so rushing into forgoing it by clever in-cam processing is really only giving away creative ground. Surely.
OK, so better night (low light) cameras have their place too. No panacea though.

But let's not overlook that it's Pentax here, and mainly its fanbois beating chests over this single standout item, all the other mfgrs seem to be content to go their own different ways.

For said fanbois: I remain unconvinced that Sony and Nikon for example, could not have easily wiped the floor in the ISO stakes with their recent equivalent offerings, if they had wanted to.

Likewise Canon took a big divergence with its new this year 60D, a path that many people simply don't understand, and slag off at them over the so-called 'downgrade' model.
The answer there is that deeper pockets translates to more power, the power to respond to and drive mass market trends and desires that only big picture market research exposes.
This also leaves Canon and Nikon to always be able to keep lower in price tags against the K-5 in shops. That matters too.

You do not win with a better mousetrap. You win with the right mousetrap.

Just like Hoya/Pentax, it all about the tangents pursued. And clearly both Canon and Nikon chose to pull very heavily toward hi-cap video functionality and usability, something that geeks are blase about.
OK, so now let's wait and see who sells the most cameras through the coming year!
And will those non Pentax buyers miss not having the biggest ISO? I doubt it.

No one really cares what camera took that great picture.

That's reality. Thanks for listening, you may plug yourself back in now.

[Psst, there's a separate forum section for lenses, with some good cud-chewing on the new 35/budget in there too.]

.R.

Last edited by Hypocorism; 11-08-2010 at 11:06 PM.
11-09-2010, 02:25 AM   #10
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it's not really about "getting enough light" for me. It's all about getting shallower DOF.

You can always increase the ISO, but you can never make the DOF thinner (on the same FOV of course).
11-09-2010, 02:57 AM   #11
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QuoteOriginally posted by Hypocorism Quote
Well said. High ISO is and always will be a trade off, no matter how much Pentax tries to make it the new pissing contest after megapixels.
Pentax is trying to make this the new pissing contest? If you hadn't noticed, high ISO has been the new pissing contest for the last three or four years, and it is only recently that Pentax has started to win or become competitive after losing the craptacular () 10 MP Sony and 14 MP Samsung sensors.


QuoteOriginally posted by Hypocorism Quote
But let's not overlook that it's Pentax here, and mainly its fanbois beating chests over this single standout item, all the other mfgrs seem to be content to go their own different ways.
You mean, like Nikon and Sony also using the identical or equivalent (awesome) 16MP sensor, with the same high ISO results, in their latest high-end APS-C cameras? How is that going a different way, at all? Everyone's just going along with the way the world is spinning, here.


QuoteOriginally posted by Hypocorism Quote
For said fanbois: I remain unconvinced that Sony and Nikon for example, could not have easily wiped the floor in the ISO stakes with their recent equivalent offerings, if they had wanted to.
The D7000 is equivalent in performance to the K-5. It doesn't and couldn't "wipe the floor" with it because it uses, for all intents and purposes, the same sensor. Wait for the A77, and watch how it is also going to be roughly equivalent to those two.


QuoteOriginally posted by Hypocorism Quote
And will those non Pentax buyers miss not having the biggest ISO? I doubt it.
I also doubt they will miss it, because they will in fact have it. I don't know what kind of dream world you live in where Pentax is the only company pursuing noise free high ISO -- the fact is that they are just now catching up to what CaNikOlympuSony has been doing for years.
11-09-2010, 04:47 AM   #12
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QuoteOriginally posted by switters Quote
Is f2.4 the new f1.8?
Pentax would like you to believe so.

Seriously, though, I normally shoot my 35/1.8G @f/2 or f/2.2, as that is a sweet spot for the center resolution anyway...and while it may be pretty sharp wide-open on a 6MP or 10MP camera, 16MP requires a little more than what it produces wide-open. Sharpness isn't everything either...but stopping down also noticeably improves the Nikon's bokeh quality as well.

A lot will be determined by how the 35/2.4 handles...if it is pretty sharp at max aperture, you aren't losing much in comparison with the competition. If it needs to be stopped down to f/2.8 or f/3.2 to jump the contrast up...then you might want to start thinking about an alternative (assuming you want to shoot in low light).

FWIW, the sigma 30/1.4 is available, but most say that it also needs to be stopped down to around f/2 to get good detail from it (assuming you get a GOOD sample). From what I've seen of the samples, the bokeh is pretty decent wide-open with the Sigma, so for artistic purposes it still has some value wide-open...and its heavy...and it ain't cheap.

Last edited by AngryCorgi; 11-09-2010 at 04:52 AM.
11-09-2010, 04:56 AM   #13
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I think it is... while there are those who will continue to look for the 1.8 and 1.4s in search of thinner DoF I believe there is a significant group who look to these lenses only for their light gathering abilities (I am typically in this group).... now, with latest generation sensors can better boost iso.
11-09-2010, 05:04 AM   #14
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QuoteOriginally posted by RolloR Quote
it's not really about "getting enough light" for me. It's all about getting shallower DOF.
It's quite the opposite for me most of the time: I want faster shutter speeds, baggy--or at least, "comfort -fit"-- DOF and as little noise as possible (think birds and sports at dusk).
11-09-2010, 05:09 AM   #15
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Have any of you who like fast glass seen this article?

An Open Letter To The Major Camera Manufacturers

Might be worth the look.
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