Help a novice: sharp or unsharp images? Should I return my X-T30?

Started 4 months ago | Discussions
ChelseaPhotographer
ChelseaPhotographer Senior Member • Posts: 1,000
Re: Lens testing

giovirovi wrote:

scokill wrote:

There is nothing wrong with the lens that I can see. A little bit of tweaking and sharpening and it looks OK to me. Not the best shots to judge sharpness though.

Thanks for your opinion. May I ask you what kind of shot would you prefer to judge the sharpness?

I reviewed your images and I can assure you that your lens and your camera are fine. What is out of focus is due to depth of field, which is normal.

If you keep on closing the aperture, you will get more depth of field, but you will start losing sharpness. Being in focus and being sharp are different things.

An APS-C camera can only resolve so much, and you are getting as much as you can from the lens and camera.

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photonut2008
photonut2008 Veteran Member • Posts: 6,164
Re: Lens testing

They're "brick wall" sharp.

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photonut2008
photonut2008 Veteran Member • Posts: 6,164
Re: Lens testing

ChelseaPhotographer wrote:

An APS-C camera can only resolve so much,

Care to elaborate on that? I was doing the math the other day and came up with about 340 MP to fully resolve f/4 on a DX sensor versus 181 MP to fully resolve f/5.6 on an FX sensor, that is what would be required before a theoretically perfect lens would be diffraction limited.

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D Cox Forum Pro • Posts: 28,941
Re: Lens testing
1

photonut2008 wrote:

ChelseaPhotographer wrote:

An APS-C camera can only resolve so much,

Care to elaborate on that? I was doing the math the other day and came up with about 340 MP to fully resolve f/4 on a DX sensor versus 181 MP to fully resolve f/5.6 on an FX sensor, that is what would be required before a theoretically perfect lens would be diffraction limited.

An APS-C sensor is most likely to have 4000 x 6000 pixels, so it can resolve only 2000 line-pairs per image height. It probably has a colour mosaic, which will almost halve that.

A good prime lens will generally resolve finer detail than the APS-C sensor can record.

Depth of field and subject movement are major causes of blur.

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Sigma fp
jrtrent Veteran Member • Posts: 6,191
Re: Lens testing

giovirovi wrote:

Hey guys, thank you so much for taking the time to help me.

I see that a common issue with the photos is represented by the aperture I am using. I am thinking to post more photos with a f6-8 aperture so you can judge better.

I appreciate this thread of yours; I had either forgotten or never known that such high optical performance was available from Fuji at so low a price. A review of your particular lens's sharpness said:

"The centre is slightly soft wide open at f/2, with the peak performance achieved in the f/2.8-f/11 range. Diffraction sets in at f/16. The edges are soft from f/2-f/2.8, sharpening up at f/4, with f/5.6-f/11 the optimum settings." https://www.photographyblog.com/reviews/fujifilm_xc_35mm_f2_review/sharpness_1

The 35mm focal length on a 1.5X APS-C sensor is my preference for about 95% of the pictures I take. I love deep depth of field, and it was easy to set the hyperfocal distance with my old film cameras due to the detailed distance and depth of field scales on their lenses. With digital, those useful scales are typically missing, so I've adopted Merklinger's rules. His book, The INs and OUTs of FOCUS, is available for download at this site:

http://www.trenholm.org/hmmerk/download.html

Put simply, when doing scenic photography with a normal or wide angle lens, if I focus on the most distant object whose sharpness is important to me (often it's the horizon), and use an aperture giving a diameter of 3-5 mm, I'll likely be happy with my pictures. For a 35mm focal length, that means keeping my aperture between f/7.1 and f/11. F/8 happens to be the sweet spot optically for my particular lens, so I shoot it there almost all the time.

JustUs7 Senior Member • Posts: 2,355
Re: Lens testing

The only other question is what focus mode you’re using? It appears you’re letting the camera choose what to focus on, thus the in focus foreground twigs and blurry background. If want to focus on the building past the tree in your fourth image, spot AF would be better and you can put the spot on the building. The tree would be blurry but the subject would be sharp. Unless the tree was your subject.

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geru Senior Member • Posts: 1,221
Re: Lens testing

giovirovi wrote:

Hi everybody.

Thank you for your help and for your kindness. I just went out to take a few pics to post here, to judge if the sharpness level is reasonable or not, since I am coming from smartphone and I really don't have a reasonable comparison. So, photos are made with a brand new X-T30 with a 35mm f2, also brand new. Simulation is classic chrome if I am not wrong.

The first 2 images are what's called acceptably sharp.

The 3rd photo i assume you were trying to shoot that Automobile in the field? Your problem with this shot is that you didn't shoot it properly. Look up the term Hyper Focal Distance/ Hyper Focus if you're going to shoot landscape or shots like that then you're going to have to learn about Hyper Focus.

The last 2 are confusing I can't find where you focused. They both seems to suffer from camera shake.

Your camera and lens are fine it's the operator who has the problem. Photography has a giant learning curve take small bites, don't become frustrated, and shoot, shoot, shoot as they say practice makes perfect.

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Gerry Winterbourne Forum Pro • Posts: 18,788
Re: Lens testing
1

D Cox wrote:

photonut2008 wrote:

ChelseaPhotographer wrote:

An APS-C camera can only resolve so much,

Care to elaborate on that? I was doing the math the other day and came up with about 340 MP to fully resolve f/4 on a DX sensor versus 181 MP to fully resolve f/5.6 on an FX sensor, that is what would be required before a theoretically perfect lens would be diffraction limited.

An APS-C sensor is most likely to have 4000 x 6000 pixels, so it can resolve only 2000 line-pairs per image height. It probably has a colour mosaic, which will almost halve that.

The mosaic doesn't reduce resolution; there's still discrete data at every pixel. What it does is reduce local colour discrimination.

A good prime lens will generally resolve finer detail than the APS-C sensor can record.

Depth of field and subject movement are major causes of blur.

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Gerry
________________________________________________________________________
I'm happy for anyone to edit any of my photos and display the results
_________________________________________________________________________
First camera 1953, first Pentax 1985, first DSLR 2006
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Gerry Winterbourne Forum Pro • Posts: 18,788
Re: Lens testing

jrtrent wrote:

giovirovi wrote:

Hey guys, thank you so much for taking the time to help me.

I see that a common issue with the photos is represented by the aperture I am using. I am thinking to post more photos with a f6-8 aperture so you can judge better.

I appreciate this thread of yours; I had either forgotten or never known that such high optical performance was available from Fuji at so low a price. A review of your particular lens's sharpness said:

"The centre is slightly soft wide open at f/2, with the peak performance achieved in the f/2.8-f/11 range. Diffraction sets in at f/16. The edges are soft from f/2-f/2.8, sharpening up at f/4, with f/5.6-f/11 the optimum settings." https://www.photographyblog.com/reviews/fujifilm_xc_35mm_f2_review/sharpness_1

That's a weird way of putting things. Diffraction doesn't "cut in" - it's always present for all lenses. As with all lenses its effects start to be noticeable round about f/4-5.6, and on APSA-C the effects are quite severe by f/11. f/16 is hardly ever useful on APS-C except for macro work.

The 35mm focal length on a 1.5X APS-C sensor is my preference for about 95% of the pictures I take. I love deep depth of field, and it was easy to set the hyperfocal distance with my old film cameras due to the detailed distance and depth of field scales on their lenses. With digital, those useful scales are typically missing, so I've adopted Merklinger's rules. His book, The INs and OUTs of FOCUS, is available for download at this site:

http://www.trenholm.org/hmmerk/download.html

Put simply, when doing scenic photography with a normal or wide angle lens, if I focus on the most distant object whose sharpness is important to me (often it's the horizon), and use an aperture giving a diameter of 3-5 mm, I'll likely be happy with my pictures. For a 35mm focal length, that means keeping my aperture between f/7.1 and f/11. F/8 happens to be the sweet spot optically for my particular lens, so I shoot it there almost all the time.

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Gerry
________________________________________________________________________
I'm happy for anyone to edit any of my photos and display the results
_________________________________________________________________________
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gerry.winterbourne@ntlworld.com

jrtrent Veteran Member • Posts: 6,191
Re: Lens testing

Gerry Winterbourne wrote:

jrtrent wrote:

"The centre is slightly soft wide open at f/2, with the peak performance achieved in the f/2.8-f/11 range. Diffraction sets in at f/16. The edges are soft from f/2-f/2.8, sharpening up at f/4, with f/5.6-f/11 the optimum settings." https://www.photographyblog.com/reviews/fujifilm_xc_35mm_f2_review/sharpness_1

That's a weird way of putting things. Diffraction doesn't "cut in" - it's always present for all lenses. As with all lenses its effects start to be noticeable round about f/4-5.6, and on APSA-C the effects are quite severe by f/11. f/16 is hardly ever useful on APS-C except for macro work.

That's interesting. Here's a quote from Bob Atkins that I've long thought was accurate:

"If you want to keep your images sharp, don't use f32 with an APS-C DSLR. The effects of diffraction are clearly visible at f32 and significantly degrade the image. Use f22 only if you have no choice. Optimal sharpness depends on the lens. For a lens with significant aberrations (e.g. a consumer zoom at maximum focal length and minimum focus distance), stopping down to f16 may give optimum results. For a lens with less aberrations (e.g. a consumer zoom used at infinity focus), optimum performance is around f11, though both f8 and f16 are very similar. For a really good lens like the EF 300/4L, with well corrected aberrations, performance may peak at f5.6, but be good from f4 to f11. f16 is acceptable, but f22 and smaller apertures should be avoided."

This, however, is an older article now, and he used an 8 mp camera. From the calculator at Cambridge in Colour I see that diffraction limits change with increasing resolution. My 6 mp DSLR is not diffraction limited at f/11, but the OP's 26 mp Fuji is already diffraction limited at f/8.

How does this translate to comparative results? For example, I just don't get the depth of field I want most of the time at f/5.6, so I'm going to stop down to f/8 and even f/11 on occasion. Does the fact that I'm not diffraction limited at those apertures with my old camera mean its output is going to look better than if I used those same apertures with the OP's kit, or will the newer camera still produce better output at those apertures despite being diffraction limited?

Edit: I'll add that the lens test I quoted used an X-A7 camera body with a 24.2 mp sensor. If we end up getting more government money, an X-T200 with that XC 35mm F2 sounds tempting. PC Mag's review (using an X-T200) also suggested that the smaller apertures are quite usable:

"It's a lens that, on today's cameras, delivers nearly as much resolution wide open as it does when stopped down, notching an excellent 2,735 lines at f/2 and settling in at a slightly better 2,800 at smaller f-stops. It hits 2,900 lines, close to outstanding, at f/8, and drops off just a little bit at f/11 (2,775 lines). The weakest resolution is at f/16, but images are still in the good range (2,440 lines). You needn't fret about distortion—there's none—nor worry about a heavy vignette." https://www.pcmag.com/reviews/fujifilm-fujinon-xc-35mm-f2

Mark Scott Abeln
Mark Scott Abeln Forum Pro • Posts: 17,176
Smartphone depth of field
1

If you want to match the depth of field of a typical smartphone, you'll have to set your aperture to something between f/8 or f/11. Then, you'll have a large depth of field and more of your scene will be sharp. But you may want to add some more sharpening at the larger f/stop settings.

Your camera likely has moderate-to-low sharpening set as default, and you may have to increase it to counteract diffraction softening which may become apparent when using f/8 and larger. Basically, the degree of diffraction softening is proportional to the f/stop, so f/16 will have double the softening as does f/8.

Your problem is very common with people who first get a large-sensor camera. You have deep scenes with lots of detail both near and far, and the only stuff that is sharply rendered is a tiny, maybe unnoticeable, part of the image.

But experienced photographers will use a shallow depth of field—like using your lens at f/2—for good benefit, where they want to strongly separate their subject from the background. But this requires a distinct subject and distinct background, without a lot of stuff in-between or in front of the subject. The classic use of shallow depth of field is portraiture, where a person is in the foreground and the background is distant, without anything else visible in the image: the subject will be clearly sharp, and the rest of the image will be blurred.

It helps if you choose a subject that is rather flat, or if you shoot it head-on, so that there isn't much depth to the subject, and you use a camera position that avoids showing too much ground or extraneous items. Of course, out-of-focus blur can be used creatively, such as framing an in-focus subject with nearby out-of-focus flowers or vegetation.

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OP giovirovi New Member • Posts: 14
Re: Lens testing

JustUs7 wrote:

The only other question is what focus mode you’re using? It appears you’re letting the camera choose what to focus on, thus the in focus foreground twigs and blurry background. If want to focus on the building past the tree in your fourth image, spot AF would be better and you can put the spot on the building. The tree would be blurry but the subject would be sharp. Unless the tree was your subject.

I was trying to focus on the house with spot focus. However what may have happened is that the zone was too big and the camera focused on the three instead.

OP giovirovi New Member • Posts: 14
Re: Lens testing

Thanks, I think I am the one who needs to improve. Thank you again for helping me.

OP giovirovi New Member • Posts: 14
Re: Smartphone depth of field
1

Thank you for your kind explanation. It really seems that rather than the camera having problems I am the one who needs to improve. Thanks again.

OP giovirovi New Member • Posts: 14
Re: Lens testing
1

Guys, I just really want to thank you all for your help and opinions. Basically everyone said that the camera and lens are fine, and that I am not shooting properly, which is very likely since are the first shots I am doing with a camera in my life. This is really rassuring, so I know I shouldn't send the camera back.

photonut2008
photonut2008 Veteran Member • Posts: 6,164
Re: Lens testing
1

D Cox wrote:

photonut2008 wrote:

ChelseaPhotographer wrote:

An APS-C camera can only resolve so much,

Care to elaborate on that? I was doing the math the other day and came up with about 340 MP to fully resolve f/4 on a DX sensor versus 181 MP to fully resolve f/5.6 on an FX sensor, that is what would be required before a theoretically perfect lens would be diffraction limited.

An APS-C sensor is most likely to have 4000 x 6000 pixels, so it can resolve only 2000 line-pairs per image height.

Then the clarification would be current APS-C sensors can "only resolve so much."

It probably has a colour mosaic, which will almost halve that.

That's not accurate, and it depends on the colors you are photographing.

A good prime lens will generally resolve finer detail than the APS-C sensor can record.

Same is true for a 135 format sensor.

Depth of field and subject movement are major causes of blur.

Not when photographing brick walls.

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Mark Scott Abeln
Mark Scott Abeln Forum Pro • Posts: 17,176
Re: Smartphone depth of field

giovirovi wrote:

Thank you for your kind explanation. It really seems that rather than the camera having problems I am the one who needs to improve. Thanks again.

It’s a really common problem. Usually, the full automatic exposure feature will avoid it by using a larger f/stop.

But using a small f/stop value does give you lots of possibilities.

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D Cox Forum Pro • Posts: 28,941
Re: Lens testing
1

photonut2008 wrote:

D Cox wrote:

photonut2008 wrote:

ChelseaPhotographer wrote:

An APS-C camera can only resolve so much,

Care to elaborate on that? I was doing the math the other day and came up with about 340 MP to fully resolve f/4 on a DX sensor versus 181 MP to fully resolve f/5.6 on an FX sensor, that is what would be required before a theoretically perfect lens would be diffraction limited.

An APS-C sensor is most likely to have 4000 x 6000 pixels, so it can resolve only 2000 line-pairs per image height.

Then the clarification would be current APS-C sensors can "only resolve so much."

It probably has a colour mosaic, which will almost halve that.

That's not accurate, and it depends on the colors you are photographing.

I think it depends on the demosaicing algorithm.

A good prime lens will generally resolve finer detail than the APS-C sensor can record.

Same is true for a 135 format sensor.

Certainly.

Depth of field and subject movement are major causes of blur.

Not when photographing brick walls.

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Sigma fp
D Cox Forum Pro • Posts: 28,941
Re: Smartphone depth of field
1

giovirovi wrote:

Thank you for your kind explanation. It really seems that rather than the camera having problems I am the one who needs to improve. Thanks again.

This is true of almost everyone on DPR, experts and beginners alike. Including me.

Don Cox

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Sigma fp
photonut2008
photonut2008 Veteran Member • Posts: 6,164
Re: Lens testing

jrtrent wrote:

From the calculator at Cambridge in Colour I see that diffraction limits change with increasing resolution. My 6 mp DSLR is not diffraction limited at f/11, but the OP's 26 mp Fuji is already diffraction limited at f/8.

Diffraction limited is really a misused term; I would instead say diffraction impaired. To say a sensor is diffraction limited at f/8 it would have to have 240 lp/mm, which works out to 88 MP on a DX sensor.

If my D500 was diffraction limited at f/13 then the most I could resolve with it using a 35mm lens at that f/stop would be about the same as I can resolve using a 90mm at f/32 (because the aperture diameters of those two lenses at those two f/stops are about the same size):

What I got was color moiré from the 35mm lens at f/13, and that means I am not diffraction limited at f/13 with that lens, I'm resolution limited.

How does this translate to comparative results? For example, I just don't get the depth of field I want most of the time at f/5.6, so I'm going to stop down to f/8 and even f/11 on occasion. Does the fact that I'm not diffraction limited at those apertures with my old camera mean its output is going to look better than if I used those same apertures with the OP's kit, or will the newer camera still produce better output at those apertures despite being diffraction limited?

Here is a comparison I did years ago between my D70 and my D300:

Again, resolution is the limitation, diffraction is an impairment. You can deal with the impairment by increasing local contrast and other sharpening techniques, and how much of that you apply will depend on your intended output (same as calculating DOF depends on viewing distance).

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