Glass or sensor limited?

SWMBO has a K100D Super with the 18-55 kit lens. About a year ago we bought the 55-300 zoom, which gets to go to Wimbledon with us. Obviously neither of these lenses is particularly special, but they do OK.

I find that both these lenses produce somewhat soft images, although they can be sharpened up to quite good in Preview or Lightroom. My question is, is the softness likely to be due to being sensor-limited (6mp rather than 16mp), in which case replacing with K30, K500, or K50 will immediately give better images? Or am I glass-limited, in which case I ought to be looking at shelling out for better lenses?

The DA 55-300 gets quite favorable reviews from users, and I have one on order myself. I plan to use it as part of a lightweight travel kit, along with the DA 16-45. The DA 18-55 is, of course, a basic kit lens that can only yield so-so results (although it is reported to be better than the comparable lenses from other manufacturers).

If you are getting results different from what others get with these lenses, it may be that you need an updated camera that allows you to test individual lenses for focus adjustment.

Joe

Tim,

Both lens models typically do pretty well sharpness-wise, especially the 55-300, when stopped down to F8 or so. I wonder if you might have an issue where the camera focus is inherently off with your camera body. What's nice about newer models, at least of the K-5 variety (not sure about K-30 or -50), is the ability to fine-adjust the focus. If you could try your lenses on another more modern Pentax DSLR, maybe you could get a better understanding of whether the softness is more due to your lenses or body. If it's a focus issue, you could send the camera and lenses in for calibration...however, the cost for that might be better spent on a new, more modern body...trying to talk you into a purchase, I guess (not my $$$ so go for it ;-) ).

Regards,

Daryl

--
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Great photography is largely a matter of perspective, both visually and mentally - Daryl Kottwitz (but probably said before )
My gallery: http://darylkottwitzphoto.smugmug.com

Are you shooting moving subjects? I don't own one, but Pentax have improved the AF system in the newer cameras. Might be the AF is lagging the subject. Of course that is just an assumption about what you're taking pictures of. You might need a camera that has lower noise at high ISO to get the shutter speed up enough 1/640ish on cloudy days for tennis players.

Can you post a full-res picture here, or a 100% crop? Those with a 55-300 wight be able to answer better.. If it's "mushy" already at 6mpx, it could be the lens, or the too slow shutter speed, or the inconsistent AF, or the low ISO performance... At f/8 @ 300mm, in the center, i'd be surprised if the 55-300 can't out-resolve a 6mp sensor.

That said, the 16 mpx sensor Pentax uses in the K5, K5ii, K30, K50, etc... is excellent. You should get many advantages upgrading bodies other than just sensor resolution... 2 years ago, I went from a *istDL to a K5. The difference was INCREDIBLE, so i would recommend you upgrade the body in any case...

You live in a world where even you new smartphone, if you have one, has more MPS that your old DSLR.

So the expectations about sharpness are also nested in our everyday look at all the other images around us — sheer number of details a sensor with a larger number of pixels and lens can deliver make old sensor's output look less sharp.

Try same lenses with a new 16MP camera.

I personally think it's unlikely to be sensor resolution, just based on the fact the OP didn't mention either heavy cropping or large prints.

...of the two is the short answer. If you upgrade to a 16 MP body, you will (baring any horrible focus issues) see a market improvement in detail/sharpness in your images for a given magnification (pixel level sharpness at 100% view may be equal or worse, but that's largely irrelevant). However you're also going to see an improvement from, let's say the DA* 55 f/1.4 vs. the kit lens at 55mm on your K100d. It just won't be as big an improvement as the increased megapixels. I'd upgrade the body first in your case. But get the kit lens with your new body and sell the old kit lens with your k100d -- the newer kit lenses are now in their 2nd or 3rd generation and have improved in sharpness since the version I believe you are likely to have.

Matt

--
... interested in .... photographs? Heh? Know what a mean? Photographs? (He asked him knowingly). Nudge nudge, snap snap, grin grin, wink wink, say no more, say no more, know what a' mean? Know what a' mean?
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It unlikely either of these lens is out-resolved by the sensor even wide open.

Therefore any softness in the image is likely to be sensor or technique related, It may well be there is no softness at all but your used to over sharpened P&S/Camera phone images.

Either way to your upgrade question , any 16mp camera is likely to out-resolve both lens this will lead to a slightly less detailed image than the sensor is capable of and due to aliasing a softer image than a better lens may produce on a 16mp body.

so in summary

your current softness issue is either sensor, expectation or technique.

a new body will give better sharpness/detail with you current lens but will give even better results with better glass (no shxt Sherlock )

Better glass will also give better results on your current body.

a thought for you though my oldest everyday used glass dates to the 90's so is over ten years old ... in that time I've gone through 5 bodies.

.... a lens is for life not just your current body.

KL Matt said:

KL Matt wrote:

...of the two is the short answer. If you upgrade to a 16 MP body, you will (baring any horrible focus issues) see a market improvement in detail/sharpness in your images for a given magnification (pixel level sharpness at 100% view may be equal or worse, but that's largely irrelevant). However you're also going to see an improvement from, let's say the DA* 55 f/1.4 vs. the kit lens at 55mm on your K100d. It just won't be as big an improvement as the increased megapixels. I'd upgrade the body first in your case. But get the kit lens with your new body and sell the old kit lens with your k100d -- the newer kit lenses are now in their 2nd or 3rd generation and have improved in sharpness since the version I believe you are likely to have.

Click to expand...

The camera actually belongs to my wife, who asserts she is satisfied with the image quality. The issue came to my attention because I've just taken over our village website, so I'm going around taking picture of the church, village hall, etc. There may be some resistance to her upgrading the camera body.

I did however manage to buy the latest version of the 18-55 (the WR) and made a test set of images (from wide open to f11 at various focal lengths) yesterday when it was nice and sunny (albeit with a 10mph wind, but even at f11 it was a 1/250 sec), and took the same shots with the original 18-55 (which came with the camera). On initial inspection, examining the images on screen, I'm not sure I can tell the difference.

Well - thanks to all for the feedback. I'll press for an upgrade of the camera body, which should also bring AF benefits.

awaldram said:

awaldram wrote:

Either way to your upgrade question , any 16mp camera is likely to out-resolve both lens this will lead to a slightly less detailed image than the sensor is capable of and due to aliasing a softer image than a better lens may produce on a 16mp body.

Click to expand...

I use it sometimes. And now I'm a bit concerned

P.S. As I remember from your previous posts you really don't like this lens. What is a real reason? Some people say it is a hidden treasure :-O

Tim Streater said:

Tim Streater wrote:

I did however manage to buy the latest version of the 18-55 (the WR) and made a test set of images (from wide open to f11 at various focal lengths) yesterday when it was nice and sunny (albeit with a 10mph wind, but even at f11 it was a 1/250 sec), and took the same shots with the original 18-55 (which came with the camera). On initial inspection, examining the images on screen, I'm not sure I can tell the difference.

Well - thanks to all for the feedback. I'll press for an upgrade of the camera body, which should also bring AF benefits.

Click to expand...

I've got the 18-55wr and think it's cr@p, well not very good anyway. I went out and bought a cheap 18-55 DAL version and that's better, if I remember correctly photozone.de weren't happy with their 18-55wr either (I know lots of conflicting info in this thread...!). By the way I have a canon 18-55 IS lens that is used on a canon and that is far better than either of my pentax's (I think this belief that the pentax kit lens is a step above the others just doesn't hold true anymore). However I do use the 18-55's a lot more at the wide end than telephoto so others may hold differing opinions.

I don't have the 55-300 but use a tamron 70-300 and have been happy with that on a K100D, GX10, K-r and now a K30, but in all cases except the K30 it's needed micro AF adjustment, (using debug mode on the K100D and GX10). I'd suggest a couple of test shots of high contrast targets with front and rear patterns that you can see at the distance you shoot at might show up any af faults with the pentax lenses. If there is any problems try searching for debug mode in this forum for instructions on how to adjust the af by s/w. I think they changed it from button presses on my K100d to needing either the pentax-hack.com way of a modset text file or the russian software that can put some pentax models in debug mode.

Personally I still like the 6mp sensor from the K100D and did some tests and couldn't see a lot of difference in resolution for screen viewing or printing cropped A4's against my 12mp K-r. However if you need to boost the shadows then the K30 is definitely better. As for the K100D camera, I never enjoyed using it that much and prefer the K-r/K30 that I also now own along side the K100D and GX10...... Gonna have to sell something one day....

I'd recommend that you stay away from uv/skylight filters as well as I've seen image degradation with them.

--
Walt
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Tim Streater said:

Tim Streater wrote:

SWMBO has a K100D Super with the 18-55 kit lens. About a year ago we bought the 55-300 zoom, which gets to go to Wimbledon with us. Obviously neither of these lenses is particularly special, but they do OK.

Click to expand...

The lenses are not limiting resolution on a 6mp body.

Tim Streater said:

I find that both these lenses produce somewhat soft images, although they can be sharpened up to quite good in Preview or Lightroom. My question is, is the softness likely to be due to being sensor-limited (6mp rather than 16mp), in which case replacing with K30, K500, or K50 will immediately give better images?

Click to expand...

More megapixels will not make an image look sharper on a computer screen, or on print sizes up to 8"x10".

I wonder about the processing. Are you shooting in raw? If so, you can and should boost the contrast, saturation and/or sharpness in post-precessing. If you're shooting jpegs, try a punchier Image Tone. If you're accustomed to seeing images from a compact camera, your idea of "sharp" may be warped in the direction of over-satured and over-sharpened.

You've tried three lenses and not seen what you want. The final possibility would be a body that is out of calibration (focus point does not line up with the target). That should be checked. I find this chart easy to use and very useful. http://www.dphotojournal.com/focus-test-chart.pdf

Greyser said:

Greyser wrote:

Greyser said:

awaldram wrote:

Either way to your upgrade question , any 16mp camera is likely to out-resolve both lens this will lead to a slightly less detailed image than the sensor is capable of and due to aliasing a softer image than a better lens may produce on a 16mp body.

Click to expand...

I use it sometimes. And now I'm a bit concerned

P.S. As I remember from your previous posts you really don't like this lens. What is a real reason? Some people say it is a hidden treasure :-O

Click to expand...

Which lens do I not like.?

the 18-55 or 55-300 kit lens.?

my personal opinion is

the 18-55 is pretty good slightly behind the current Nikon/Canon equivalent offerings but not bad.

the 55-300 is a very good lens on a similar footing to the Sigma 70-300 Apo or Tamron 70-300.

not quite the diamond in the rough some owners wax lyrically about but not rubbish either.

All are probably over taxed by a 16mp sensor.

Hi Tim,

I'd say it's a bit of both, more MP's and better glass will help, but there's more to it than that, a lot more. There are techniques and tips that will give you sharper photos even with a "kit' lens or older camera. If you're already using these, I apologize in advance. There's no way to tell how much exoerience another member may have.

Are you stopping the lens down or shooting wide open? Very few, if any, lenses are at their best wide open. Even a 1/2 stop down will improve the resolution, corner sharpness and I.Q.

Are you using a lens hood? Flare, glare and ghosting will cut contrast, making the photo appear hazy or flat.

Higher shutter speeds. Even the tinest bit of camera shake will 'fuzz out' whatever sharpness the lens/camera is capable of. A photo shot (hand-held) with the kit zoom will usually be sharper at 1/250s than at 1/125s, all things being equal

Camera support. If conditions are such that slow shutter speeds (1/90 down to 1/15s) must be used, a monopod or tripod will save the day. Also, raising the ISO might get the shutter speeds back where they're safe to hand hold. A 'noisy' photo that's otherwise sharp is much better than a blurry one at ISO 100!

But, more MP's and better lenses are great, too!

Ron

awaldram said:

awaldram wrote:

Click to expand...

awaldram said:

Which lens do I not like.?

the 18-55 or 55-300 kit lens.?

Click to expand...

I was talking about DA 16-45/4, as you could see in the title of my post

Greyser said:

Greyser wrote:

Greyser said:

awaldram wrote:

Which lens do I not like.?

the 18-55 or 55-300 kit lens.?

Click to expand...

I was talking about DA 16-45/4, as you could see in the title of my post

Click to expand...

Yet neither Tim nor myself mentioned this lens!!!

So I'm totally lost by your comments

Tim asked about the 18-55 and 55-300 on a k100d

I replied

It unlikely either of these lens is out-resolved by the sensor even wide open.

then you said

Is DA 16-45 that bad?

Tim Streater said:

Tim Streater wrote:

SWMBO has a K100D Super with the 18-55 kit lens. About a year ago we bought the 55-300 zoom, which gets to go to Wimbledon with us. Obviously neither of these lenses is particularly special, but they do OK.

I find that both these lenses produce somewhat soft images, although they can be sharpened up to quite good in Preview or Lightroom. My question is, is the softness likely to be due to being sensor-limited (6mp rather than 16mp), in which case replacing with K30, K500, or K50 will immediately give better images? Or am I glass-limited, in which case I ought to be looking at shelling out for better lenses?

Click to expand...

In terms of resolution (one component of perceived sharpness along with acutance) the MP count is much more significant than the lens. The best-resolving Pentax lens tested by Photozone is the DA70/2.4. Its peak centre resolution on 16MP (K-5) is 2706; the 18-55 is 2604 (at 28mm). That's a loss of 4%. At the corners the numbers are 2422 and 2232; a loss of about 8.5%. There's a bigger difference at other FLs, though.

At 10MP (K10) the DA70 peaks at 2238; a loss of about 17% from 16MP. On 6MP it would be something under 2000, or about 25% loss from 16MP.

In other words, going from 6MP to 16MP will increase resolution by about 25%; going from a kit lens to a top prime at any MP will increase resolution by something like 10%. So in terms of resolution alone the upgraded body is much the best buy. Note, too, that you get this sort of improvement with every lens you own, while buying a better lens only improves things for the FL range it covers.

Sharpening, which is actually increasing acutance, doesn't (can't) improve resolution. The image might - indeed, it usually does - look better, but there is no increase in the resolution of fine detail. With higher resolution, though, you get better fine detail and you can still sharpen it if you want to for improved perceived sharpness.

Finer resolution is also better for picking up fine tonal and colour distinctions.

Don't be fooled by the idea that viewing size is irrelevant: although you have to down-size, you get a better down-sized image if you start from a better original. The reason is the same as why it's bad practice mathematically or statistically to average averages.

Gerry Winterbourne said:

Gerry Winterbourne wrote:

Gerry Winterbourne said:

Tim Streater wrote:

SWMBO has a K100D Super with the 18-55 kit lens. About a year ago we bought the 55-300 zoom, which gets to go to Wimbledon with us. Obviously neither of these lenses is particularly special, but they do OK.

I find that both these lenses produce somewhat soft images, although they can be sharpened up to quite good in Preview or Lightroom. My question is, is the softness likely to be due to being sensor-limited (6mp rather than 16mp), in which case replacing with K30, K500, or K50 will immediately give better images? Or am I glass-limited, in which case I ought to be looking at shelling out for better lenses?

Click to expand...

In terms of resolution (one component of perceived sharpness along with acutance) the MP count is much more significant than the lens. The best-resolving Pentax lens tested by Photozone is the DA70/2.4. Its peak centre resolution on 16MP (K-5) is 2706; the 18-55 is 2604 (at 28mm). That's a loss of 4%. At the corners the numbers are 2422 and 2232; a loss of about 8.5%. There's a bigger difference at other FLs, though.

At 10MP (K10) the DA70 peaks at 2238; a loss of about 17% from 16MP. On 6MP it would be something under 2000, or about 25% loss from 16MP.

In other words, going from 6MP to 16MP will increase resolution by about 25%; going from a kit lens to a top prime at any MP will increase resolution by something like 10%. So in terms of resolution alone the upgraded body is much the best buy. Note, too, that you get this sort of improvement with every lens you own, while buying a better lens only improves things for the FL range it covers.

Click to expand...

Thanks, that's quite helpful. I guess my perceptions of what is sharp or not comes from shooting Kodachrome 25 with Pentax camera going back to the Spotmatic, but most recently with an M-ZM and an f1.4 Pentax FA 50mm lens.

With the K100D super I usually stop down to f5.6 or f8 if I can, with a lens hood and typically a UV filter.

Now, someone replying to this thread, and sorry I can't find the post right now, suggested I use Tim Jackson's focus test chart, which I just did, using my old FA lens I refer to above, open to f1.4 to get the smallest DoF. I attach the result. Test conditions were not ideal as I had to hand-hold it and approximate to 45deg. But the implication is that the camera focus needs adjusting.




Focus test



--
Tim

What sort of light was that under, as AWB looks all over the shop.

The camera uses its WB to set Focus correction for light wavelength.

if you have wrong WB then focus will likely be off.

This may well be the issue your seeing

White Balance {0xA403} = manual (1)

Why do you have WB off auto and obviously mis-set for the enviroment