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Discussion Starter · #1 · (Edited)
Ok so the only way i seem to be able to do forced perspective is cranking the aperture up to f32 or higher which results in a slightly blurry image over all with my lenses.
Any Suggestions?





 

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You are trying to increase your "depth of focus" and that does indeed depend on your lenses and available light.

The smaller aperature cuts a lot of light. Have you tried manually focusing on the loco (with normal aperature) and then taking several shots, not touching the focus but stopping down the aperature?

I suspect you are at the limit of your lens on your camera...

Greg
 

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Discussion Starter · #3 ·
You are trying to increase your "depth of focus" and that does indeed depend on your lenses and available light.

The smaller aperature cuts a lot of light. Have you tried manually focusing on the loco (with normal aperature) and then taking several shots, not touching the focus but stopping down the aperature?

I suspect you are at the limit of your lens on your camera...

Greg
Ok so tripod mount the camera and take several shots at different focal points? But how do i combine the different focused layers?
 

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Now do you 'crank the aperture' up or down to get to f32.
My Dad always referred to a 'smaller' hole, being down.
Anyway, not too sure why you are worrying, the photos look great to me and the lack of depth of field doesn't bother me, in fact I would think it look strange if both the front and the rear of a locomotive were in perfect focus.
But you need to Photoshop the wires out, they do bother me!!!!
Cheers,
David Leech, Delta, Canada
 

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To each his own, I agree that the focus is not sharp.

I did not recommend trying to combine shots... the several shots might be manually varying the focus a bit.

Are you doing this with autofocus? I'd focus manually, especially with a small aperature, the camera does not know where to focus... and then there are focus zones, number, etc. Don't know what your camera can do.

I have a Sony A2000, take the autofocus to a single point, very small, then do focus hold to compose the picture.

Greg
 

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Discussion Starter · #6 ·
Now do you 'crank the aperture' up or down to get to f32.
My Dad always referred to a 'smaller' hole, being down.
Anyway, not too sure why you are worrying, the photos look great to me and the lack of depth of field doesn't bother me, in fact I would think it look strange if both the front and the rear of a locomotive were in perfect focus.
But you need to Photoshop the wires out, they do bother me!!!!
Cheers,
David Leech, Delta, Canada
I think the way your dad stated it was the correct way.
 

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There is a technique called 'focus stacking' that can allow you to extend the apparent focal depth of a photograph. It isn't simple but there are a variety of software packages that will help. You mount the camera on a tripod and take a series of photographs focused progressively down the subject at an optimum aperture such as F8. You then use the software to merge these images. The results can be spectacular and it is widely used in Macro photography where the depth of field otherwise is fractions of a millimeter.

Having said that, I agree with an earlier post that photographs can look better with the right choice of depth of field and some part of the image slightly blurred.

Robert
 

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I find that a typical photo is taking close by, which causes problems. For example a shot of a loco at an angle, where the smokebox is in focus and the tender is blurred. I see this all the time.

By using a telephoto/zoom, and getting further away, and then zooming to fill the frame, you will have a larger depth of focus.

Greg
 

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Ok so the only way i seem to be able to do forced perspective is cranking the aperture up to f32 or higher which results in a slightly blurry image over all with my lenses.
Any Suggestions?
One other technique might help. Instead of focusing on the front of the engine, set the focus about 1/3 of the way down. The way to think of this is that if you focus on the front, then the zone of sharp focus will include areas ahead of the locomotive.

You can actually calculate the numbers. For a full frame 35mm camera with a 50mm lens and the subject 6 feet away, the depth of field at F8 is 2.11 feet with a zone of sharpness running from 5.12 feet to 7.24 feet. At F11, the depth of field extends to just over 3 feet - enough for most G Scale locomotives. There are a couple of APPs for iPhone that calculates this for you.

Robert
 

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really? no offense, you must have been using crummy lenses... and I also stated zoom...

Again, the idea is to be able to get just far enough away to increase the depth of focus, not shoot a picture from a mile away.

Greg
 

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I hesitate to open a can of worms here, but this is a subject full of myths, misconceptions and optical illusions. There is, for example, no intrinsic depth of field benefit from a telephoto lens. If you compare a 200mm lens to a 50mm lens, then the depth of field for a given f stop is the same if you compensate for the magnification of the lens by moving further away. In other words, the depth of field for a 50mm lens 6 feet away from a subject is the same as for a 200mm lens 24 feet away and can be proved mathematically.

This assumes perfect lenses and no camera shake. In the real world, the perceived depth of field can be greater if the photo overall is less sharp as a result of poorer lens quality or camera shake.

Guess who had to write a paper on the performance of optical systems at college :)

Robert
 

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Hide behind the insult....

Maybe you can read and educate yourself:


read the section about zooming in on this page... of course you can state that everyone else is wrong. I was talking about zoom, and telephoto lens usually have zoom.... I'm not talking long range, but the ability to move away from the subject, and then zoom in to fill the frame.

Of course I guess this guy in the link is wrong too....

I think the pot calling the kettle black is good for you Mr. Leech....
 

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Quote from the document you reference "So focal length does not actually influence DoF if you adjust the camera-subject distance so that the magnification of your subject is the same." . I think this is exactly what I was saying.

Not sure what I said that was insulting. Anyway, signing off this thread.......
 

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Was not you, it was Mr Leech I was replying to... you posted while I was typing, note the time stamps on my post #15 and your post #16 are basically the same time.

I agree with you Z, and again for anyone confused, from the article:

Did even more reading, and again would like to know the camera used, apparently many cameras focus with the aperture open, and then when you take the picture "stopped down" there is something called "focus shift" that can cause issues.

In any case, I agree with the OP, the focus is just not sharp.

Greg
 

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I'm surprised no one here has suggested changing the number of pixels. I may be wrong, but isn't that the same as changing the ASA on a film camera. OF course it may also effect the amount of light recorded.
 

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I'm surprised no one here has suggested changing the number of pixels. I may be wrong, but isn't that the same as changing the ASA on a film camera. OF course it may also effect the amount of light recorded.
ASA has now been replaced by ISO, but it still is the measurement of light recorded. In other words film sensitivity to light. You would pick a more sensitive ISO film or digital camera ISO setting on the sensor for fast shutter speeds so that you can capture quick movement and not have the picture turn out dark.

Changing the image size (pixels x pixels size) in the image settings on a DSLR just changes the size of the final digital JPEG or RAW image, it will not help with focus or focal length issues, that must be corrected by using the right lens, f-stop, and distance from the subject.
 

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Changing the number of pixels would just degrade the image. Reducing them would reduce the detail, and increasing them is putting data where none existed, interpolating, would worsen the sharpness, what this is about.

Still want to hear from the OP what camera and lens is being used.
 
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