topic Re: G9 X - Picture edges unfocused on close range in Point & Shoot Digital Cameras

G9 X - Picture edges unfocused on close range

AnthonyD — Sat, 13 Jan 2018 18:39:42 GMT

I just bought a PowerShot G9 X.

For close range photos the center focus is good, but the edges are out of focus. I've partially overcome this effect by selecting an edge for the focus frame, but then the center is out of focus though not as bad as the edges were. No matter what I try the focus is uneven and makes for bad close range photos. This camera is brand new.

My older, lower-end PowerShot A2500 HD manages to focus the whole shot evenly. See the attached photo comparisson.

My two questions are:

1) Is this normal or is something wrong with my camera?

2) If this is normal, can I change it so the focus is even across the image?

Thanks!

PowerShot G9 X

(not the mark ii version)

Re: G9 X - Picture edges unfocused on close range

John_ — Sat, 13 Jan 2018 21:57:55 GMT

Since the print you took a picture of is all at the same distance all of it should either be in or out of focus. How close was the lens? And was it in Macro mode? Pehaps it was your close distance at a slight angle and you were not in Macro mode? If not try macro mode and check the focus specs vs. distance and shooting modes for your camera. I do hope it is not something wrong with your new camera. Others will respond too with more advice. Since it is new you can call Canon for help as another option.

Re: G9 X - Picture edges unfocused on close range

AnthonyD — Sat, 13 Jan 2018 22:46:00 GMT

@John_ wrote:
Since the print you took a picture of is all at the same distance all of it should either be in or out of focus. How close was the lens? And was it in Macro mode? Pehaps it was your close distance at a slight angle and you were not in Macro mode? If not try macro mode and check the focus specs vs. distance and shooting modes for your camera. I do hope it is not something wrong with your new camera. Others will respond too with more advice. Since it is new you can call Canon for help as another option.

I took several different shots and they are all like that. There was a bit of improvement at acute angles, where there normally should be problems. Yes, I deliberately set it to macro mode for some of the tests, with the same result. I tested at distances from 5 cm to 1.5 feet and the effect is still there. Longer distances seem also affected but much less.

Here is a shot with me placing the focus frame on the edge, I don't remember if it was right or left, but either way improves the edges somewhat but blurs the center.

Re: G9 X - Picture edges unfocused on close range

ScottyP — Sun, 14 Jan 2018 04:59:25 GMT

On every lens the edges will be less sharp than the center. Additionally, some lenses, even expensive ones, notably like the Canon EF 50mm f/1.2, the field of focus is not a flat plane but rather a curved shape so that the edges will always be out of focus.

Re: G9 X - Picture edges unfocused on close range

ScottyP — Sun, 14 Jan 2018 05:04:33 GMT

If you are serious about photographing text get a tilt shift lens. If you are less serious but need to do it, use a normal lens but a high f/stop for a thick depth of field in focus.

Re: G9 X - Picture edges unfocused on close range

Waddizzle — Sun, 14 Jan 2018 09:12:01 GMT

@ScottyP wrote:
On every lens the edges will be less sharp than the center. Additionally, some lenses, even expensive ones, notably like the Canon EF 50mm f/1.2, the field of focus is not a flat plane but rather a curved shape so that the edges will always be out of focus.

What he is describing is the primary fundamental difference between a conventional lens and a macro lens. A conventional lens creates a curved plane of focus with the image sensor at the center of the arc. A macro lens produces a much flatter plane of focus.

Under most conventional shooting scenarios the curved focus plane of conventional lens goes largely unnoticed, because of the larger depth of field that you find associated with larger distances to the subjects that you have in most shooting scenarios: i.e.; a photo of your dog, or a bridge.

The large distance to the subjects, creates a large radius, and a fairly flat focus plane. The curve becomes irrelevant because by the time the plane curves outside of a flat DOF, the distance to the camera is so great that subjects are out of focus, anyway. Many shots that seem soft o the edges are soft because they should be. Objects at the edge of the frame are outside of the curved DOF.

When you start taking photos on a macro scale, the depth of field becomes much smaller, and the short radius of the focal plane comes into play. This is why your images seem to lose focus as you move away from the center of the frame, which is where the focus plane intersects the subject.

The flatter image plane of a macro lens reduces the apparent loss of sharpness at the edges when photographing flat subjects. Also, this flat plane of focus makes it easier for software to perform what is known as image stacking of a set of macro images. Image stacking combines a set of sequence of photos of a subject, where each photo has only a portion of the subject in focus, into a single composite image where the entire subject is in focus.

Re: G9 X - Picture edges unfocused on close range

MikeSowsun — Sun, 14 Jan 2018 10:53:17 GMT

One thing to note is that the G9X has a much larger sensor than the A2500, and that means less Depth of Field for a similarly framed image. That could explain why the A2500 is better able to get sharp corners.

Re: G9 X - Picture edges unfocused on close range

Waddizzle — Sun, 14 Jan 2018 12:41:21 GMT

I frequently eyeball this table before I go out on a shoot. Select a camera with the same sensor size as yours.

http://www.dofmaster.com/doftable.html

It helps me to select lenses, and choose focal lengths. It is a bit dated, when it comes to camera selection. But, the size of sensors really has not changed. For example, I select the EOS 7D when I am using any APS-C DSLR by Canon.

You have to scroll way down the list to find PowerShot cameras.

Re: G9 X - Picture edges unfocused on close range

newsense52 — Sun, 14 Jan 2018 15:08:58 GMT

In macro mode make these setting: Light metering center weighted average, select f=8 or higher, auto focus off - use manual zooming, distance is 12 inches and no flash on.

I see as no dof is involved because it is a one plane surface, only it focuses on center or edge, and distribution of light is not even to all surfaces.

Re: G9 X - Picture edges unfocused on close range

AnthonyD — Sun, 14 Jan 2018 18:21:16 GMT

Thanks for the replies everyone, but I really need to determine if this camera is faulty or not. If it's faulty then I have to ship it back to Amazon, a task I'm not looking forward to and would prefer to avoid. If this is actually normal, then maybe I can learn to live with it. It's not the easiest thing to reasearch, is it: "Is this camera good for taking close-up pictures of small text without screwing up everything outside the immediate center?"

One of the main reasons I chose this camera was to take close up pictures of text, because it has stabilization and works well in the dark without the flash glare. What's the point if most of the image is out of focus? The manual says absolutely nothing about this issue, which adds more reason to think it's defective. "This model features macro mode! Too bad it sucks compared to your old crappy camera. Now fork over 4x the price please."

Another thing, let's say I return a perfectly fine camera, buy another one and encounter the same thing?

Re: G9 X - Picture edges unfocused on close range

AnthonyD — Sun, 14 Jan 2018 18:29:51 GMT

@Waddizzle wrote:
I frequently eyeball this table before I go out on a shoot. Select a camera with the same sensor size as yours.

http://www.dofmaster.com/doftable.html

It helps me to select lenses, and choose focal lengths. It is a bit dated, when it comes to camera selection. But, the size of sensors really has not changed. For example, I select the EOS 7D when I am using any APS-C DSLR by Canon.

You have to scroll way down the list to find PowerShot cameras.

I don't mean to be rude, but what the hell am I supposed to do with that chart? I'm not a photographer, just a regular point and shoot person. The only part that I could make sense of is "Circle of confusion".

Re: G9 X - Picture edges unfocused on close range

John_ — Sun, 14 Jan 2018 19:09:21 GMT

Anthony I'm just a point and shoot person too your camera is new and if I were you I'd call Canon and see if they have any ideas outside of buying a different camera and lenses etc.etc or if maybe they will replace yours with a new one. I still don't think what your seeing is normal and it makes no sense how it switches from bad middle to edge focus....get it on record contact Canon. I looked thru your manual and saw no "disclamers" like you can expect poor edge or center focus if you shoot like you did.

Re: G9 X - Picture edges unfocused on close range

AnthonyD — Sun, 14 Jan 2018 19:27:02 GMT

Thanks John, your answer is the most helpful (and sensible). Why would they make a camera that's supposed to perform this badly? If I'm messing around with manual program functions and causing the problem, that's well and good, but if Auto setting is causing the problem and I have to work around with finicky manual settings, and STILL not get a satisfactory picture, then something's very wrong. Either the camera is defective or it just sucks. I hope it's the former rather than the latter.

I'm returning it to Amazon. What a bunch of stupid annoying trouble. I wish it was clearly damaged, like with big holes or tears in the images, or something easy to determine as defective. These subtle issues take longer to spot, lead to debates over the cause, and mean I have to go through a painstakingly meticulous testing process the next time I buy a camera. Why waste my time doing actual productive work when I could invest it on trying to figure out if my camera is bad?

Thands, I'll mark your answer as the solution.

Re: G9 X - Picture edges unfocused on close range

John_ — Sun, 14 Jan 2018 20:03:49 GMT

Your welcome Anthony and thankfully Amazon has a great return policy procedure. Your right those hidden, subtle problems dont always show up so fast. Consider an extended warranty with your next choice too. I wish you the best of luck. By the way I have the SX50HS and have taken many close shots both macro and just close up and never experienced what you have with the focus.