Railfan Technology > What's Causing This

Along the edges of white letters or light bright shapes in my pics with this one lens I get these weird ghostly highlights. I don't think it's a focus or shake issue. But maybe I'm wrong, I'm sort of a novice at understanding cameras. Let me know. I lost the lens hood for this lens so could that be causing it? Is it overexposure?

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This could be a Chromatic Aberration with the lens assembly, and having more scattered light (missing the hood) might exacerbate it.

http://en.wikipedia.org/wiki/Chromatic_aberration



Edited 1 time(s). Last edit at 08/12/14 11:56 by nicknack.

It doesn't appear to be sharp at all. Either a focus error,mirror slap, subject movement, camera movement.

We need to know the ISO, shutter speeed nd apeture before we can help much. Put the camera on a tripod, lock the mirror up and use a remote release. Then see what you have. But realistically you need to have the shutter speed higher than you may surmise. At least 1/500 and better at 1/1000 on a close in shot.

Does appear to be a focus issue. Look at the words in yellow and they appear fuzzy too.

Probably a focus issue; the whole photo is fuzzy. Because of the out of focus gravel I'd suspect you are using too low (numerically) an f-stop. If you are shooting in Auto mode the camera is probably using a low f-stop with a high shutter speed in order to capture what it believes is enough light to get the proper exposure.

The old method of testing a lens sharpness was to tape a newspaper classified ad section to a wall and then shoot several shots at different f-stop setting and then check for sharpness, especially at the edges. If you try this use a tripod and do it in an area with a lot of natural light.

I didn't want to comment earlier as I was looking at this on a iPhone. But after reviewing the image on a desktop computer, I agree that the image is just soft overall. If it's just happening with one lens, time to investigate the characteristics and limitations of that lens.

It's really hard to say what's up with your photo... There's no exif info, so I'm in the dark.

The repost here has been run through unsharp mask. Any photo out of a camera is going to need a bit of help.

1. I don't know about the camera or the lens: what are they.

2. Was the posted shot a jepg out of the camera, or a RAW image that has been manipulated.

3. What is the size of the original image...

John.

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The right side of the photo seems to show more of the issue than the left. Not sure if it's due to the subject being closer to you on the left vs the right or something else.

Ryan Wilkerson
Fair Oaks, CA

Is this a cropped image?

I really appreciate your for help folks.

Lens: tamron AF aspherical LD IF 28-200mm nikon
Camera: Nikon D70s

The image is cropped from the full one below.

Here's the settings: iso200/f5.6/1/1600.

I agree it looks out of focus. I'm using autofocus in aperture priority mode. But I think the out of focus is more from this weird thing around the bright edges where they seem to bleed over the dark areas they're next to. The red parts of the ballast car don't look out of focus is another piece. Check out the full pic below and another crop from it of a guy's hat and the yellow lettering on car. I think that shows the weird effect later.

So do you think it's a aperture thing--the 5.6 being incredibly unsharp?

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One other possibility, is the lens clean...???
I have had similar looking issues on rare occasion, sometimes with a bad smear on the lens, or a drop of sweat?

Just something to look at...

Are they in the process of dumping ballast when you took the shot? If so, could you be getting reflective glare from the dust that is kicking up?

In the larger photo, you can clearly see the dust around the truck toward the left side of the frame. I'm wondering if the light reflecting off the lettering and brighter objects is catching the dust in a likewise fashion.



Edited 1 time(s). Last edit at 08/13/14 19:54 by bioyans.

skyview Wrote:
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> One other possibility, is the lens clean...???
> I have had similar looking issues on rare
> occasion, sometimes with a bad smear on the lens,
> or a drop of sweat?
>
> Just something to look at...

Especially the crop of the worker in the hard hat...resembles a dirty lens.

Because you are not looking at a 90 degree angle to the car, the right side is farther away than the left side. Your problem is a lack of depth of field. If your depth of field is shallow (determined by the F stop and focal length), then both ends of the car may not be in sharp focus. To get more depth of field, use a higher f stop, or a shorter focal length lens.

ddavies Wrote:
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> Because you are not looking at a 90 degree angle
> to the car, the right side is farther away than
> the left side. Your problem is a lack of depth of
> field. If your depth of field is shallow
> (determined by the F stop and focal length), then
> both ends of the car may not be in sharp focus.
> To get more depth of field, use a higher f stop,
> or a shorter focal length lens.

That wouldn't explain why the ballast on the left side is also OOF.

The entire shot looks fuzzy/out of focus to me.

I'm a Canon guy so I'm not familiar with your particular lens. Does your lens have IS (image stabilization)? If it doesn't and these are hand held shots using focal lengths greater than 70mm then that may be your problem. It takes a very steady hand to keep a camera perfectly still especially if there's any wind.

I use a tripod 95% of the time shooting trains. It's a pain to set up of course especially when you are following a scene that's moving horizontally (like a ballast train dumping rock). In that case I'll use a monopod or handheld with wide angle lens.

I'd also start reviewing your photos in the field by using the magnification button on your camera. I do this on a regular basis especially if I'm shooting people at weddings and other people events where the focus on the person is critical. Better to redo the photo then to get home and be dissapointed.

I'll go with cheap 'protection' filter or too slow shutter speed. Presuming this was a zoomed in shot at 200mm, it's also a known photography issue that very, very few lenses are sharpest at their aperture and zoom extremes.

thanks for the input folks. I will keep all of it in mind and do some experimenting.

Most camera's have the ability to individually save corrected focus values for different lenses. Take a ruler and lay it out on the table in front of you and spot focus on a single mark on the ruler. Then look that the pic to see if its in focus where you shot. If the focus point is before or after the mark, auto correct it in the camera and retry till it is correct.

I have a similar Tamaron 70-300mm lens on SD70. The overall sharpness is better than that, but bright objects such as those letters will get purple fuzz at full zoom due to chromatic aberration. I have to remind myself, it is a $200 Tamaron, not a $1000 Nikon. But your lens should zoom in sharper than that.

Scott Schifer
Torrance, CA
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