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50mm f1.4 problem - nothing in focus?

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Dave Gowenlock

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I tried my Kenko extension tubes today with my 50mm f1.4 and only the middle of the frame is ever sharp. Everything else looks funny, what am I doing wrong?



Seriously though - consider this an extreme shallow DOF image thread. Lets see how little you guys/gals managed to focus on...

Dave
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Kit List is On My Profile
http://www.davidgowenlock.co.uk
Landscape and nature photography from around the world
 
this IS an extremely shallow DOF question.

how much extension tube were you using? 12mm? 20? 36?

were you focussed at 'infinity' on the lens? what was the subject distance?

what was your aperture? if it wasn't at least f/8, I would be surprised if anything was sharp at all - at macro distances, you are fighting to get even a couple inches of DOF when stopped down!

was the subject lying parallel to the sensor? were there parts projecting in front or behind the plane of focus?

we need more information from you in order to help you better!

cheers,
S.
--
My XT IS Full Frame -- APS-C/FF of course!
So is my 5D -- 35mm/FF
 
I'm not surprised!

When I'm having a bad day, my 50 1.4 sometimes feels like the DOF could split atoms when wide open and close focussed, I dread to think what it would be like with extension tubes :)
--
Matt
 
Dave Gowenlock said:
I tried my Kenko extension tubes today with my 50mm f1.4 and only the
middle of the frame is ever sharp. Everything else looks funny, what
am I doing wrong?



Seriously though - consider this an extreme shallow DOF image thread.
Lets see how little you guys/gals managed to focus on...

Dave
Click to expand...
I think what you have here is all tubes stacked together. Probably the image plane is not flat when the 50 f 1.4 is extended that far, and DOF becomes so shallow, so can't compensate. You can try to hold the lens inverted on the tubes and see how that looks.
 
ScottyNV said:
we need more information from you in order to help you better!
Click to expand...
Sorry, I hope I havn't mislead anyone. I was shooting at f1.8 with the 36mm and 12mm tubes, which gives a magnification of roughly 1. I was expecting a tiny DOF but hadn't realised how tiny it would be!

I would love to see other similar photos, where they isolate a tiny subject with an even tinyier DOF.

Regards,
Dave
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Kit List is On My Profile
http://www.davidgowenlock.co.uk
Landscape and nature photography from around the world
 
photonius said:
Probably the image plane is not flat when the 50 f 1.4 is extended that far,
and DOF becomes so shallow, so can't compensate. You can try to hold
the lens inverted on the tubes and see how that looks.
Click to expand...
Thank you for your reply. What shape does the image plane become, curved? I had assumed the curved plane of focus in the picture was due to the leaves not all being flat and on the same plane. I would be very interested to hear if it is actually due to the lens.

Dave
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Kit List is On My Profile
http://www.davidgowenlock.co.uk
Landscape and nature photography from around the world
 
MattWeth said:
When I'm having a bad day, my 50 1.4 sometimes feels like the DOF
could split atoms when wide open and close focussed, I dread to think
what it would be like with extension tubes :)
Click to expand...
Thats what I am talking about - if you have any photos of this I would love to see them :D Be careful with that camera!

Dave
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Kit List is On My Profile
http://www.davidgowenlock.co.uk
Landscape and nature photography from around the world
 
How 'bout this for little DoF...shot with 75-300 @ 300mm @ 5.6(iicr)
TS400
[/URL]
 
Dave Gowenlock said:
photonius said:
Probably the image plane is not flat when the 50 f 1.4 is extended that far,
and DOF becomes so shallow, so can't compensate. You can try to hold
the lens inverted on the tubes and see how that looks.
Click to expand...
Thank you for your reply. What shape does the image plane become,
curved? I had assumed the curved plane of focus in the picture was
due to the leaves not all being flat and on the same plane. I would
be very interested to hear if it is actually due to the lens.

Dave
Click to expand...
You can find out if you take a picture
of a piece of paper with small text or something on it.
Focus the lens back and forth, and you will see what aspect is due to DOF,
and what to curvature. Each lens is different.

Here is an example of an unusual field curvature.

http://www.photozone.de/Reviews/Canon%20EOS%20Lens%20Tests/289-tamron-af-17-50mm-f28-sp-xr-di-ii-ld-aspherical-if-canon-test-report--review?start=1

normally curvature tends to go the other way.
 
When I looked at your photo, I thought you had a lot of DOF for macro work; its usually much tighter and restricitive than what your photo is showing. You don't shoot that far away in macro mode, get that lens in there, if you can't see the eyes of your bug, what's the point?

Some one above said in macro DOF you are restricted to "inches" but this is false; the average macro freak would love even one inch of focus. Usually you are dealing in 1/4 inches or less, most often much less.

A fast lens is wasted in the macro world as you will be shooting with smaller aperatures to get better detail, roughly f8 or f11 or you might try and push it to f16 depending on your lens and its smallest aperature.
--
Maybe the writing on the wall could use a little revision
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http://www.youtube.com/watch?v=f02Q5IFoyKw&NR=1
 
rsn48 said:
When I looked at your photo, I thought you had a lot of DOF for macro
work; its usually much tighter and restricitive than what your photo
is showing. You don't shoot that far away in macro mode, get that
lens in there, if you can't see the eyes of your bug, what's the
point?
Click to expand...
Unfortunatly I had just got my macro tubes that evening and there were no bugs out to photograph. I look forward to catching some little critters un-awares though :D
rsn48 said:
Some one above said in macro DOF you are restricted to "inches" but
this is false; the average macro freak would love even one inch of
focus. Usually you are dealing in 1/4 inches or less, most often
much less.
Click to expand...
I agree - the leaves in my photo are roughly 1.5mm in diameter so the DOF really is small (compared to everyday shots). Had there been a bug in the photo I would have only got it's nose in focus! The reason of taking the picture was to see exactly how little DOF I got at f1.8 with the new tubes.

Do you have any photos to share?

Dave
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Kit List is On My Profile
http://www.davidgowenlock.co.uk
Landscape and nature photography from around the world
 
The majority of my macros are plants, with a few bugs, but I"m not happy with the quality of my bug photos. I have bought a new macro lens - Sigma 150 f2.8 - and a new Sigma flash ring, so I'll be hunting the little buggers myself soon.

In actual fact, I plan on cheating. At my house in Qualicum Beech on Vancouver Island, I live very close to "Butterfly World" so soon I will have some great butterfly pics.

My next problem is I am just learning Elements 6 and I haven't been successful in converting my RAW's to JPEG's so I can post. I'm not a bad photographer but right now I am pathetically photo editing software challenged.
--
Maybe the writing on the wall could use a little revision
Shane Koyczan (Slam Poet)
http://www.youtube.com/watch?v=f02Q5IFoyKw&NR=1
 
The 50mm 1.4 were used with a 12mm ET.

http://www.pbase.com/dkord/image/43050601.jpg

http://www.pbase.com/dkord/image/89229375.jpg

http://www.pbase.com/dkord/image/89231006.jpg

I think I used a 20mm ET with my 50 1.4 on this spider shot:

http://www.pbase.com/dkord/image/43634552.jpg

The 70-300 IS had a 20mm ET.

http://www.pbase.com/dkord/image/80905757.jpg

http://www.pbase.com/dkord/image/84350830.jpg

http://www.pbase.com/dkord/image/82471877.jpg

I love using these ETs but as you can see I'm more conservative on it's usage.
No massive tight in anatomy shots.
 
My guess is the photo was taken at f1.4? No depth of field there, the image distance from the edge of the subject to the sensor plane differs too much from the center of the field where you focused.
Try it again at f8 and let us know.
rgds
 
rsn48 said:
My next problem is I am just learning Elements 6 and I haven't been
successful in converting my RAW's to JPEG's so I can post. I'm not a
bad photographer but right now I am pathetically photo editing
software challenged.
Click to expand...
What camera are you using? I tried so many RAW converters and spent ages evaluating them all. My favourite is Canon Digital Photo Professional - it comes with all Canon SLRs. I found it makes the most natural looking pictures and most need no post processing. It is a doddle to use and really well made. No good if your not a Canon user though!

Look forward to seeing some of your shots.

Dave
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Kit List is On My Profile
http://www.davidgowenlock.co.uk
Landscape and nature photography from around the world
 
dkord said:
I love using these ETs but as you can see I'm more conservative on
it's usage.
No massive tight in anatomy shots.
Click to expand...
I likes the first photo - the flower looks like it's exploding into the frame. IMO you need a warning on the spider shot - it made my skin crawl!!

I really like the last three - great captures. Fantastic colour on the butterfly and nice job catching the dragon fly mid flight!!

Thanks for sharing
Dave
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Kit List is On My Profile
http://www.davidgowenlock.co.uk
Landscape and nature photography from around the world
 
Just to chime-in with another sample. This is with the 50mm f1.4 and a 12mm ET. As others have said, I have learned over time that I need a really small hole to make good use of the ET. This was at f22 (and on a 10D).

 
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