[linds]

Hi All,

I've looking to purchase a II or IIs K-5 (currently own a K-x). I've been obsessively comparing the images of the 2 cameras but can't for the life of me decide on which one to go for. The summary of my research is:

- IIs is great for cropping, which I do a lot of as my lenses don't quite have the reach or crop quite heavily when doing macro work of insects

- IIs looks sharper in general (but II images can get very close if you're prepared to spend time PP'ing them correctly)

- Moire doesn't seem to be common enough to be a problem. I don't plan on doing Wedding photos. It's appearance on the eyes of insects (like a fly) has been shown to occur on one particular photo I've stumbled on, can possibly be avoided though

On this next point, I'd be interested to hear if others share the same view on the IIs, or whether my eyes aren't use to seeing the images.

With landscapes in particular, objects in the background seem to be sharper than what my eyes would normally pick up seeing the scene "in the flesh". I understand that when you stop down enough you're ultimately going to resolve more detail in a picture than what the human eyes will pick up, but the IIs seems to up this a level where the image appears somewhat flat with it's depth. Again it might just take some getting used to and it's not a criticism of the camera at all. Anyone else get this impression?

I've heard a few people say to get the most out of the IIs, you need to use it with Prime lenses.

I have these lenses:

- Tamron 17-50 2.8
- Tamron 90mm macro
- Tamron 70-200 2.8
- Sigma 18-125mm

Is the IQ of these lenses really going to be out of the league of harnessing the extra sharpness that the IIs can deliver?

Thanks in advance to any info on this that can help with my decision

Cheers,
Lindsay

[Adam]

The first three should be, yes, as long as you don't stop them down too much. Another great lens is the FA 77mm.

[linds]

The first three should be, yes, as long as you don't stop them down too much. Another great lens is the FA 77mm.

Thanks for the info Adam- re not stopping down too much, if I was for example to stop down the 17-50 to F22 on a landscape shot, I'd be at risk of impacting the IQ negatively? To what level would this effect the image? (i.e. would the same shot on a K-5 II be more forgiving at this fstop?)

[fs999]

I don't think your lenses will impact a lot in IQ loss, because they where made for full frame cameras (with the exception of the 18-125, I would take a DA 15 in place of this lens).

[goubejp]

To keep the extra resolution of the K5iis you don't stop beyond f8; after f11 the diffraction degrades seriously image quality

[Digitalis]

or example to stop down the 17-50 to F22 on a landscape shot, I'd be at risk of impacting the IQ negatively? To what level would this effect the image? (i.e. would the same shot on a K-5 II be more forgiving at this fstop?)

yes, using f/22 would have a massively negative impact on image quality. An image taken at f/22 on the Pentax K5IIs will still be slightly sharper than an image taken at the f/22 on the regular K5II because of the missing bayer AA filter - however to really reap the benefits of the K5IIs keep the aperture around f/5.6 which is where most lenses perform their best. No 35mm lens ever performs well at f/22 - for landscape photography I suggest using f/11 besides most high performance prime lenses start to lose image quality a few stops after f/5.6. At f/11 you still have enough DOF to cover large subjects, at f/13 fine details start to lose acutance at f/16 diffraction is visibly detectable. It is important to note that sharpening an image doesn't recover detail lost to diffraction, it only makes the details that have been captured clearer.

[Adam]

Thanks for the info Adam- re not stopping down too much, if I was for example to stop down the 17-50 to F22 on a landscape shot, I'd be at risk of impacting the IQ negatively? To what level would this effect the image? (i.e. would the same shot on a K-5 II be more forgiving at this fstop?)

At F22 the IQ is going to be significantly worse than at F11. The visible benefits of the filterless design end around F8, and they peak at even wider apertures, so I'd try to shoot around F4.5 or 5.6 when possible.

Adam
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[fs999]

I don't know if it is really a problem. This shot was taken at F32 !

[linds]

I don't think your lenses will impact a lot in IQ loss, because they where made for full frame cameras (with the exception of the 18-125, I would take a DA 15 in place of this lens).

A DA15 would be nice- although the problem is I would also like an UWA lens like an 8-16 or 10-20...

[Digitalis]

A DA15 would be nice- although the problem is I would also like an UWA lens like an 8-16

At wider f/ stops the Sigma 8-16mm lens has better image quality that the DA15, at f/11 the DA15 has more CA in the corners than the sigma lens. With the hood down the DA 15mm f/4 ASPH Limited is slightly less than half the size of the sigma 8-16mm lens.Another consideration to take into account is that there is quite a bit of sample variation in the Sigma 8-16mm - the first one I bought was slightly decentred, the first DA15 I bought was perfect*.



*the funny thing is my DA15mm f/4 ASPH Limited is assembled in Vietnam, my sigma 8-16mm f4.5-5.6 was made in Japan. The my current 8-16mm lens is perfectly centred. I will be doing a head to head test with the DA15mm f/4 Vs the Sigma 8-16mm lens on my Pentax K5IIs shortly.

[linds]

yes, using f/22 would have a massively negative impact on image quality. An image taken at f/22 on the Pentax K5IIs will still be slightly sharper than an image taken at the f/22 on the regular K5II because of the missing bayer AA filter - however to really reap the benefits of the K5IIs keep the aperture around f/5.6 which is where most lenses perform their best. No 35mm lens ever performs well at f/22 - for landscape photography I suggest using f/11 besides most high performance prime lenses start to lose image quality a few stops after f/5.6. At f/11 you still have enough DOF to cover large subjects, at f/13 fine details start to lose acutance at f/16 diffraction is visibly detectable. It is important to note that sharpening an image doesn't recover detail lost to diffraction, it only makes the details that have been captured clearer.

Thanks for the info- looks like I had a bit of a misconception re stopping down and sharpness

At F22 the IQ is going to be significantly worse than at F11. The visible benefits of the filterless design end around F8, and they peak at even wider apertures, so I'd try to shoot around F4.5 or 5.6 when possible.

Cheers Adam.

There's some pretty good looking images at F22 out there. Like this one, could have been extra sharp at F11 though it sounds like it:

[Digitalis]

There's some pretty good looking images at F22 out there. Like this one, could have been extra sharp at F11 though it sounds like it:

That is why the ability to be able to use filters with your lenses is rather important, Neutral density (ND) filters allow you to use longer exposures without the requirement to stop your lens all the way down and kiss all that resolution goodbye.


Pentax K-7 with DA15mm f/4 limited and Lee "big stopper" 10 stop ND filter

[linds]

Yep I remember seeing this picture in another thread- great pic!

[linds]

Digitalis: do you still prefer to own the Sigma 8-16mm over the 10-20mm considering the trouble of getting an ND filter on it?

[Digitalis]

well since I still own my DA15mm f/4 limited I can use than in situations where a strong ND filter would be useful for effect, or where distortion needs to be kept in check. But i'm using the Sigma 8-16mm because it is much sharper at wider apertures than the DA15mm f/4 is, and not to mention the 8mm focal length which is considerably wider than the DA15.