Is f2.4 the new f1.8?

**NaClH2O** · 11-09-2010, 05:20 AM

Originally posted by Ash

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.

True and some long time prime enthusiasts also.

NaCl(I'm pretty sure I'm going to sell my FA 35mm F2.0 and get the DA 35mm F2.4)H2O

**Lowell Goudge** · 11-09-2010, 05:39 AM

Originally posted by AGWoodard

Have any of you who like fast glass seen this article?

An Open Letter To The Major Camera Manufacturers

Might be worth the look.

Actually it might not be worth the look

I did some tests, using my K50F1.4 on my *istD, K10D and K7D.

What is interesting in the article, is that the article starts off by saying that this is an issue with CMOS sensors more than CCD, but the worst performing camera is a Nikon with a CCD.

What I found with my 3 bodies, when shooting at the same lens aperture and shutter speed is that the greyscale value in the center of the frame was within about 1/10th of a stop between F1.4, F2 and F2.8 on all 3 cameras. Each camera seemed to be calibrated slightly different, but within the camera there was no difference. What I also noticed is that all cameras (or more likely the lens) had some vignetting in the corner, worth about 3/4 of a stop on all bodies which was removed by F2.

Now, unless the manufacturers are boosting exposure/iso only in the corners, the entire article is BS

see more in the general photography forum

paperbag846 · 11-09-2010, 07:20 AM

Originally posted by Hypocorism

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.

This isn't a brand X vs. brand Y conversation - we are discussing the merits of fast glass. You really took the conversation into your own little world there.

As far as fast-glass goes, well I sit in the middle. Before, speed was necessary for DOF AND to be able to shoot in low light. Most journalists would use their 35mm f2 lenses at f8 unless they were standing indoors. However people forget that when the objective is exposure in dim lighting, a thin DOF is a compromise to get proper exposure as well! Sure, high ISO is not preferable to low ISO, but by the same token, a picture shot at f 1.8 indoors is going to have all sorts of softness associated with it compared to one shot at 2.4/2.8.

So this high iso is a compromise thing I don't really see. Fast aperture is a compromise too! There is one exception - when you want that blurry "special effect". You either do or you do not. Certainly, an entry-level prime is not going to have those features, hence the 35mm 2.4. The low DOF effect is useful for creative types, and they will be more than happy to pay the premium, but in many cases, one extra stop of ISO might be better so you can keep everything in focus.

Here's two pictures from jerk with a camera Shoot with Dawn Today which show the practical difference between f 1.4 and 2.8. It's noticeable, that's for sure. The question is how many images do you want to look like 1.4?

f1.4

f2.8

Remember, you pay for that aperture. Large aperture increases the total volume of materials required to build the lens, amongst other things. Many canon primes (non 50mm) cost well over 1000 dollars to be in the f1.4 range! Pentax has taken a significantly different approach which I find quite interesting. Fast glass is certainly available (especially if you are comfortable with manual focus) but, for the most part, they seem to have decided that most people really only need f2.0.

switters · 11-09-2010, 07:42 AM

Great discussion, everyone.

It's timely because I'm trying to decide right now whether to stick with Pentax or go back to full-frame, either a Sony a850 or a used 5D II. A brief history: I shot with a Canon 5D for a long while, doing mostly personal but some professional work, but then for various reasons sold my gear. About a year later, I decided to pick up a camera again but I wasn't ready to spend a few grand so I just bought a Pentax K-x and a single lens (50/1.4).

I am one of those "creative types", alas, so the 5D was perfect for me. I had a 50/1.4 and a 100/2, along with a 28-75/2.8. That was all I needed. The DOF of the 50/14 on full-frame is something else, and while, yes, it was pretty soft at that aperture the creative effect was a lot of fun. These are not the $1,000+ Limited lenses I was using - all were well under $500, both were fast, and they were perfectly good for my needs paired with the 5D. I also loved that a 50mm lens was 50mm, and a 100mm lens was 100mm.

I suppose I could pick up a used 5D, but I got so frustrated with the dust and lack of proper weather sealing that I vowed I'd never do that again. I consider the a850 or a used 5D II, but it's a bit more than I'd like to spend at this point.

That's what brought me to the K-5. Seems the sensor performs better than any other APS-C. But the problem, for me, is the lack of fast primes in my price range at the desired focal length. I want a 50mm EFL f1.4, and a 100mm EFL f1.8 or f2. The 70mm f2.4 is 105mm and gets close in terms of aperture, and since it's a longer lens I think I could live with it being a bit slower. The 35 f2.4 is a bigger compromise, though.

Ah well, I'll have to give it more thought.

paperbag846 · 11-09-2010, 07:56 AM - **1 Like**

Originally posted by switters

I want a 50mm EFL f1.4, and a 100mm EFL f1.8 or f2. The 70mm f2.4 is 105mm and gets close in terms of aperture, and since it's a longer lens I think I could live with it being a bit slower. The 35 f2.4 is a bigger compromise, though.

Ah well, I'll have to give it more thought.

With a 500 dollar price range, you could find yourself the FA 35 2.0. The 50mm 1.4 is no slouch, and can be found used for 300.

PS I did not mean to disparage creative photography! I just wanted to point out that the utility of fast glass is becoming more and more relegated to that of creative photography... the more practical side (i.e., taking a picture in low light) aspect of it is more a non-issue these days.

However, if you are getting paid for your creativity, I certainly see that as a practical issue!

Do you like manual focus? There is all sorts of fast glass to be hard in the manual focus arena.

switters · 11-09-2010, 08:18 AM

paperbag846,

I didn't think you were disparaging creative photography. Actually, the point you're making was the one I meant to make when I started this thread.

So I agree with you - a fast aperture is more about DOF now, and what that permits, than it is about low-light. Yes, IQ is worse at higher ISO, but the same can be said for most lenses used at f1.4.

Is the 35/2 still easy to find? That and the 70/2.4 might do the trick for me. The other consideration is that the 35/2.4 has a pretty short MFD. That means that if I need more OOF / thinner DOF, I could in some cases just get closer to my subject.

I enjoy manual focus, but I'm not good enough at it to be able to capture moving subjects reliably.

junyo · 11-09-2010, 08:26 AM

It's not just about DOF either; shutter speed matters. If you're shooting anything that moves, in low light, you need all the aperture you can get. In jazz clubs, sometimes I'm lucky to get 1/90 @ f2.8/ISO12800. Having a couple of extra stops via a f1.4 lens gives me flexibility, to back down the ISO, to stop down for more depth, or to go to a faster shutter speed.

This whole "you don't need a bigger aperture because you've got clean high ISO' meme is a bunch of BS.

switters · 11-09-2010, 08:28 AM

I don't disagree, junyo. That's why I'm considering going back to full-frame in a different mount. There just aren't any fast lenses I can afford in the desired focal length range in Pentax's line-up.

Nass · 11-09-2010, 08:35 AM

I picked up a f1.2 50 last week. What I'm finding interesting about it is not actually the speed aspect at all but the bokeh/blur at 1.2. One thing though is that it's quite easy to add extra background blur in photoshop if you really need it. Having that extra blur does seem to make more of a difference than I had anticipated but then I've never had or even played with a particularly fast lens in my life so it's all a novelty to me.

I think where I'd find a higher ISO cam useful wouldn't be what you can do with it at those higher ISOs in the middle of the night/indoors but that you could use 800 instead of 100 for regular shots with no effect. I often find that I'm using a slower shutter speed than I really should or a higher ISO than I really should to get certain shots given light conditions.

paperbag846 · 11-09-2010, 08:38 AM

Originally posted by junyo

This whole "you don't need a bigger aperture because you've got clean high ISO' meme is a bunch of BS.

Need and want are two different things. Before, you needed it or your picture would turn out black. Now, you want it so you can use a lower ISO. However, just as in the olden days, you do sacrifice image quality in a different way. Different strokes, different folks... I've shot a few concerts wide open (1.7), and ended up stopping down a bit because I could not get more than one person on stage in focus. I found the lighting acceptable enough that I could swing 2.4/2.8, which also made my center sharpness better. ISO never went over 1600.

The FA 2.0 is not readily available and is currently overpriced. I don't expect it will hold it's "cult" pricing indefinitely, and I would suggest that the 2.4 alternative is pretty good considering the price difference / optical difference. Also, one review in the review section for the lens comments that the lens actually acts more like an f2.2, for what it is worth.

The DA 70 2.4 looks quite stunning, but if you are doing paid work again, you might want to consider a used FA 77 - a little more length, and a little faster, but it's also optically a different beast and the OOF areas are really quite smooth. The DA 70 is the one I would buy, because the price is right.

EDIT: One of pentax's major strengths is not the fastest etc. - it's ergonomics. My friend (pro) is a Canon man. I've learnt a lot from him, and he has never steered me wrong (although he did suggst I stay away from Pentax... that is, until I showed him what I could do with some old 50 dollar lenses!) He has lots of fast glass. But everything he owns is about 1.5X the size of mine, or more! Even his cheap 50mm 1.8 prime is huge compared to my 50's. In general I do think pentaxians make sacrifices for size... but that's one of the major attractions to the brand. Slap a limited pancake on a pentax and you have very good IQ in a very small package... just like the good old days. A pro canon/nikon set up screams "LOOK OUT- PHOTOGRAPHER HERE!". Seriously, those rigs can be BIG.

Pentax is not the best at everything... but I would argue that no brand is.

Winder · 11-09-2010, 08:40 AM

Pentax needs to keep producing the cheaper f/2.4 glass to sell with their K-x/K-r bodies. Pentax has a budget customer that they have to respect and provide for.

Hopefully the K-5 and the 645D are signs that the professional quality equipment is going to make a comeback. The A* 85mm and A* 135mm would be very welcome additions to the modern line-up. A DA* 85mm f/1.4 & DA* 135mm f/1.8 would really fill some gaps in the Pentax line-up.

The new Sigma 85mm f/1.4 appears to be a strong contender, but the more options the better.

**Rondec** · 11-09-2010, 08:58 AM

I seldom shoot wider than 2.8. A lot of f1.4 lenses are soft wide open and unless you want a soft, sort of dreamy look, stopping down is the way to go. The problem with a lot of f2 and f2.4 lenses is just that you have get to f4 to get them sharp. It looks to me like the DA 35 f2.4 is an exception -- a lens that is quite sharp wide open.

As paperbag says, there are compromises either way. Soft photos from high iso or shooting wide open are still soft photos and you have to figure out a way to get your photos where you want them, in whatever light you are shooting.

GeneV · 11-09-2010, 09:19 AM

I'll answer the original question "yes" in the sense that F2.4 now represents a fast lens. Here are a few of my reasons why the aperture mark has moved over the 35 years I've been shooting Pentax:

1) This is a zoom world. Cameras come with zooms. F2.4 is faster than the vast majority of zooms which are the majority of lenses. A prime at F2.4 is now fast compared to the alternatives as a whole.

2) With or without the K5, ISO is in another realm on a DSLR from the time when F1.8 was a standard on a 50mm. As a film shooter, I was a low-ISO junkie shooting lots of Kodachrome for color and stretching up to ISO 400 TX for B&W, but shooting a lot of slow B&W as well. There isn't even a setting for the ISO I used most years ago. Now, higher ISOs produce far better quality.

3) Because of the DOF, I used F 1.8, 1.4 or 1.2 to compensate for light very seldom back then and even less now. The creative use is there, but it is not something I need often.

4) One of the biggest reasons to buy a fast lens--ease of manual focus--is not as important today. Yes, I do still focus manually, and AF is more accurate with a larger aperture, but in most viewfinders, one is not reminded of the disadvantages of a smaller aperture quite the way that dark split image circle in the middle of the viewfinder brought the point home. Also, the precision of the plane of focus you gain from a large aperture is less important when the cameras focus point is not indicated with precision.

5) One other reason why I bought lenses with large apertures was to get good performance stopped down to something like F2.8 or 4. Now, it seems that lenses with max apertures in that range are good from wide open.

Don't get me wrong, fast glass is very cool. I'm not getting rid of any fast lenses, and I'll probably add more. However, I do "get" why F2.4 might be taking the place in the market of the F1.8 as a max aperture for lenses.

paperbag846 · 11-09-2010, 09:20 AM

Originally posted by Rondec

The problem with a lot of f2 and f2.4 lenses is just that you have get to f4 to get them sharp. It looks to me like the DA 35 f2.4 is an exception -- a lens that is quite sharp wide open.

I actually do not find this to be the case with most of Pentax's slower primes (e.g., the whole DA limited line) they do get sharper as you stop down, but they are pretty sharp wide open, just like the 35 2.4.

junyo · 11-09-2010, 09:33 AM

Originally posted by paperbag846

Need and want are two different things. Before, you needed it or your picture would turn out black. Now, you want it so you can use a lower ISO. However, just as in the olden days, you do sacrifice image quality in a different way. Different strokes, different folks... I've shot a few concerts wide open (1.7), and ended up stopping down a bit because I could not get more than one person on stage in focus. I found the lighting acceptable enough that I could swing 2.4/2.8, which also made my center sharpness better. ISO never went over 1600.

Not sure of your point here; the tradeoff is fundamentally the same. "So you can use lower ISO" is the exact same reason fast glass has always been useful. And it's not like we haven't seen these arguments before (let's not forget the advertising of "grain-free ISO800 speed films, and the last few generations of print film with enormous exposure latitudes).

But the fact remains, for a given EV/ISO combination, faster glass offers a wider range of f stop/shutter speed combinations.

11-09-2010, 08:38 AM	#25
paperbag846 Veteran Member Join Date: Jul 2010 Photos: Gallery Posts: 2,395	Originally posted by junyo This whole "you don't need a bigger aperture because you've got clean high ISO' meme is a bunch of BS. Need and want are two different things. Before, you needed it or your picture would turn out black. Now, you want it so you can use a lower ISO. However, just as in the olden days, you do sacrifice image quality in a different way. Different strokes, different folks... I've shot a few concerts wide open (1.7), and ended up stopping down a bit because I could not get more than one person on stage in focus. I found the lighting acceptable enough that I could swing 2.4/2.8, which also made my center sharpness better. ISO never went over 1600. The FA 2.0 is not readily available and is currently overpriced. I don't expect it will hold it's "cult" pricing indefinitely, and I would suggest that the 2.4 alternative is pretty good considering the price difference / optical difference. Also, one review in the review section for the lens comments that the lens actually acts more like an f2.2, for what it is worth. The DA 70 2.4 looks quite stunning, but if you are doing paid work again, you might want to consider a used FA 77 - a little more length, and a little faster, but it's also optically a different beast and the OOF areas are really quite smooth. The DA 70 is the one I would buy, because the price is right. EDIT: One of pentax's major strengths is not the fastest etc. - it's ergonomics. My friend (pro) is a Canon man. I've learnt a lot from him, and he has never steered me wrong (although he did suggst I stay away from Pentax... that is, until I showed him what I could do with some old 50 dollar lenses!) He has lots of fast glass. But everything he owns is about 1.5X the size of mine, or more! Even his cheap 50mm 1.8 prime is huge compared to my 50's. In general I do think pentaxians make sacrifices for size... but that's one of the major attractions to the brand. Slap a limited pancake on a pentax and you have very good IQ in a very small package... just like the good old days. A pro canon/nikon set up screams "LOOK OUT- PHOTOGRAPHER HERE!". Seriously, those rigs can be BIG. Pentax is not the best at everything... but I would argue that no brand is. Last edited by paperbag846; 11-09-2010 at 08:43 AM.

11-09-2010, 05:20 AM	#16
NaClH2O Site Supporter Join Date: Sep 2006 Location: Bronx NY Photos: Gallery \| Albums Posts: 5,631	Originally posted by Ash 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. True and some long time prime enthusiasts also. NaCl(I'm pretty sure I'm going to sell my FA 35mm F2.0 and get the DA 35mm F2.4)H2O

11-09-2010, 05:39 AM	#17
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,891	Originally posted by AGWoodard Have any of you who like fast glass seen this article? An Open Letter To The Major Camera Manufacturers Might be worth the look. Actually it might not be worth the look I did some tests, using my K50F1.4 on my *istD, K10D and K7D. What is interesting in the article, is that the article starts off by saying that this is an issue with CMOS sensors more than CCD, but the worst performing camera is a Nikon with a CCD. What I found with my 3 bodies, when shooting at the same lens aperture and shutter speed is that the greyscale value in the center of the frame was within about 1/10th of a stop between F1.4, F2 and F2.8 on all 3 cameras. Each camera seemed to be calibrated slightly different, but within the camera there was no difference. What I also noticed is that all cameras (or more likely the lens) had some vignetting in the corner, worth about 3/4 of a stop on all bodies which was removed by F2. Now, unless the manufacturers are boosting exposure/iso only in the corners, the entire article is BS see more in the general photography forum

11-09-2010, 07:20 AM	#18
paperbag846 Veteran Member Join Date: Jul 2010 Photos: Gallery Posts: 2,395	Originally posted by Hypocorism 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. This isn't a brand X vs. brand Y conversation - we are discussing the merits of fast glass. You really took the conversation into your own little world there. As far as fast-glass goes, well I sit in the middle. Before, speed was necessary for DOF AND to be able to shoot in low light. Most journalists would use their 35mm f2 lenses at f8 unless they were standing indoors. However people forget that when the objective is exposure in dim lighting, a thin DOF is a compromise to get proper exposure as well! Sure, high ISO is not preferable to low ISO, but by the same token, a picture shot at f 1.8 indoors is going to have all sorts of softness associated with it compared to one shot at 2.4/2.8. So this high iso is a compromise thing I don't really see. Fast aperture is a compromise too! There is one exception - when you want that blurry "special effect". You either do or you do not. Certainly, an entry-level prime is not going to have those features, hence the 35mm 2.4. The low DOF effect is useful for creative types, and they will be more than happy to pay the premium, but in many cases, one extra stop of ISO might be better so you can keep everything in focus. Here's two pictures from jerk with a camera Shoot with Dawn Today which show the practical difference between f 1.4 and 2.8. It's noticeable, that's for sure. The question is how many images do you want to look like 1.4? f1.4 f2.8 Remember, you pay for that aperture. Large aperture increases the total volume of materials required to build the lens, amongst other things. Many canon primes (non 50mm) cost well over 1000 dollars to be in the f1.4 range! Pentax has taken a significantly different approach which I find quite interesting. Fast glass is certainly available (especially if you are comfortable with manual focus) but, for the most part, they seem to have decided that most people really only need f2.0.

11-09-2010, 07:42 AM	#19
switters Veteran Member Join Date: Jul 2007 Posts: 346 Original Poster	Great discussion, everyone. It's timely because I'm trying to decide right now whether to stick with Pentax or go back to full-frame, either a Sony a850 or a used 5D II. A brief history: I shot with a Canon 5D for a long while, doing mostly personal but some professional work, but then for various reasons sold my gear. About a year later, I decided to pick up a camera again but I wasn't ready to spend a few grand so I just bought a Pentax K-x and a single lens (50/1.4). I am one of those "creative types", alas, so the 5D was perfect for me. I had a 50/1.4 and a 100/2, along with a 28-75/2.8. That was all I needed. The DOF of the 50/14 on full-frame is something else, and while, yes, it was pretty soft at that aperture the creative effect was a lot of fun. These are not the $1,000+ Limited lenses I was using - all were well under $500, both were fast, and they were perfectly good for my needs paired with the 5D. I also loved that a 50mm lens was 50mm, and a 100mm lens was 100mm. I suppose I could pick up a used 5D, but I got so frustrated with the dust and lack of proper weather sealing that I vowed I'd never do that again. I consider the a850 or a used 5D II, but it's a bit more than I'd like to spend at this point. That's what brought me to the K-5. Seems the sensor performs better than any other APS-C. But the problem, for me, is the lack of fast primes in my price range at the desired focal length. I want a 50mm EFL f1.4, and a 100mm EFL f1.8 or f2. The 70mm f2.4 is 105mm and gets close in terms of aperture, and since it's a longer lens I think I could live with it being a bit slower. The 35 f2.4 is a bigger compromise, though. Ah well, I'll have to give it more thought.

11-09-2010, 07:56 AM - 1 Like	#20
paperbag846 Veteran Member Join Date: Jul 2010 Photos: Gallery Posts: 2,395	Originally posted by switters I want a 50mm EFL f1.4, and a 100mm EFL f1.8 or f2. The 70mm f2.4 is 105mm and gets close in terms of aperture, and since it's a longer lens I think I could live with it being a bit slower. The 35 f2.4 is a bigger compromise, though. Ah well, I'll have to give it more thought. With a 500 dollar price range, you could find yourself the FA 35 2.0. The 50mm 1.4 is no slouch, and can be found used for 300. PS I did not mean to disparage creative photography! I just wanted to point out that the utility of fast glass is becoming more and more relegated to that of creative photography... the more practical side (i.e., taking a picture in low light) aspect of it is more a non-issue these days. However, if you are getting paid for your creativity, I certainly see that as a practical issue! Do you like manual focus? There is all sorts of fast glass to be hard in the manual focus arena.

11-09-2010, 08:18 AM	#21
switters Veteran Member Join Date: Jul 2007 Posts: 346 Original Poster	paperbag846, I didn't think you were disparaging creative photography. Actually, the point you're making was the one I meant to make when I started this thread. So I agree with you - a fast aperture is more about DOF now, and what that permits, than it is about low-light. Yes, IQ is worse at higher ISO, but the same can be said for most lenses used at f1.4. Is the 35/2 still easy to find? That and the 70/2.4 might do the trick for me. The other consideration is that the 35/2.4 has a pretty short MFD. That means that if I need more OOF / thinner DOF, I could in some cases just get closer to my subject. I enjoy manual focus, but I'm not good enough at it to be able to capture moving subjects reliably.

11-09-2010, 08:26 AM	#22
junyo Veteran Member Join Date: Oct 2007 Photos: Gallery Posts: 418	It's not just about DOF either; shutter speed matters. If you're shooting anything that moves, in low light, you need all the aperture you can get. In jazz clubs, sometimes I'm lucky to get 1/90 @ f2.8/ISO12800. Having a couple of extra stops via a f1.4 lens gives me flexibility, to back down the ISO, to stop down for more depth, or to go to a faster shutter speed. This whole "you don't need a bigger aperture because you've got clean high ISO' meme is a bunch of BS.

11-09-2010, 08:28 AM	#23
switters Veteran Member Join Date: Jul 2007 Posts: 346 Original Poster	I don't disagree, junyo. That's why I'm considering going back to full-frame in a different mount. There just aren't any fast lenses I can afford in the desired focal length range in Pentax's line-up.

11-09-2010, 08:35 AM	#24
Nass Veteran Member Join Date: Aug 2009 Location: The British Isles Photos: Gallery Posts: 2,402	I picked up a f1.2 50 last week. What I'm finding interesting about it is not actually the speed aspect at all but the bokeh/blur at 1.2. One thing though is that it's quite easy to add extra background blur in photoshop if you really need it. Having that extra blur does seem to make more of a difference than I had anticipated but then I've never had or even played with a particularly fast lens in my life so it's all a novelty to me. I think where I'd find a higher ISO cam useful wouldn't be what you can do with it at those higher ISOs in the middle of the night/indoors but that you could use 800 instead of 100 for regular shots with no effect. I often find that I'm using a slower shutter speed than I really should or a higher ISO than I really should to get certain shots given light conditions.

11-09-2010, 08:40 AM	#26
Winder Veteran Member Join Date: Apr 2010 Location: Tennessee Posts: 6,617	Pentax needs to keep producing the cheaper f/2.4 glass to sell with their K-x/K-r bodies. Pentax has a budget customer that they have to respect and provide for. Hopefully the K-5 and the 645D are signs that the professional quality equipment is going to make a comeback. The A* 85mm and A* 135mm would be very welcome additions to the modern line-up. A DA* 85mm f/1.4 & DA* 135mm f/1.8 would really fill some gaps in the Pentax line-up. The new Sigma 85mm f/1.4 appears to be a strong contender, but the more options the better.

11-09-2010, 08:58 AM	#27
Rondec Loyal Site Supporter Join Date: Mar 2009 Location: Gladys, Virginia Photos: Gallery Posts: 27,663	I seldom shoot wider than 2.8. A lot of f1.4 lenses are soft wide open and unless you want a soft, sort of dreamy look, stopping down is the way to go. The problem with a lot of f2 and f2.4 lenses is just that you have get to f4 to get them sharp. It looks to me like the DA 35 f2.4 is an exception -- a lens that is quite sharp wide open. As paperbag says, there are compromises either way. Soft photos from high iso or shooting wide open are still soft photos and you have to figure out a way to get your photos where you want them, in whatever light you are shooting.

11-09-2010, 09:19 AM	#28
GeneV Veteran Member Join Date: Oct 2008 Location: Albuquerque NM Photos: Albums Posts: 9,830	I'll answer the original question "yes" in the sense that F2.4 now represents a fast lens. Here are a few of my reasons why the aperture mark has moved over the 35 years I've been shooting Pentax: 1) This is a zoom world. Cameras come with zooms. F2.4 is faster than the vast majority of zooms which are the majority of lenses. A prime at F2.4 is now fast compared to the alternatives as a whole. 2) With or without the K5, ISO is in another realm on a DSLR from the time when F1.8 was a standard on a 50mm. As a film shooter, I was a low-ISO junkie shooting lots of Kodachrome for color and stretching up to ISO 400 TX for B&W, but shooting a lot of slow B&W as well. There isn't even a setting for the ISO I used most years ago. Now, higher ISOs produce far better quality. 3) Because of the DOF, I used F 1.8, 1.4 or 1.2 to compensate for light very seldom back then and even less now. The creative use is there, but it is not something I need often. 4) One of the biggest reasons to buy a fast lens--ease of manual focus--is not as important today. Yes, I do still focus manually, and AF is more accurate with a larger aperture, but in most viewfinders, one is not reminded of the disadvantages of a smaller aperture quite the way that dark split image circle in the middle of the viewfinder brought the point home. Also, the precision of the plane of focus you gain from a large aperture is less important when the cameras focus point is not indicated with precision. 5) One other reason why I bought lenses with large apertures was to get good performance stopped down to something like F2.8 or 4. Now, it seems that lenses with max apertures in that range are good from wide open. Don't get me wrong, fast glass is very cool. I'm not getting rid of any fast lenses, and I'll probably add more. However, I do "get" why F2.4 might be taking the place in the market of the F1.8 as a max aperture for lenses.

11-09-2010, 09:20 AM	#29
paperbag846 Veteran Member Join Date: Jul 2010 Photos: Gallery Posts: 2,395	Originally posted by Rondec The problem with a lot of f2 and f2.4 lenses is just that you have get to f4 to get them sharp. It looks to me like the DA 35 f2.4 is an exception -- a lens that is quite sharp wide open. I actually do not find this to be the case with most of Pentax's slower primes (e.g., the whole DA limited line) they do get sharper as you stop down, but they are pretty sharp wide open, just like the 35 2.4.

11-09-2010, 09:33 AM	#30
junyo Veteran Member Join Date: Oct 2007 Photos: Gallery Posts: 418	Originally posted by paperbag846 Need and want are two different things. Before, you needed it or your picture would turn out black. Now, you want it so you can use a lower ISO. However, just as in the olden days, you do sacrifice image quality in a different way. Different strokes, different folks... I've shot a few concerts wide open (1.7), and ended up stopping down a bit because I could not get more than one person on stage in focus. I found the lighting acceptable enough that I could swing 2.4/2.8, which also made my center sharpness better. ISO never went over 1600. Not sure of your point here; the tradeoff is fundamentally the same. "So you can use lower ISO" is the exact same reason fast glass has always been useful. And it's not like we haven't seen these arguments before (let's not forget the advertising of "grain-free ISO800 speed films, and the last few generations of print film with enormous exposure latitudes). But the fact remains, for a given EV/ISO combination, faster glass offers a wider range of f stop/shutter speed combinations.