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Author Topic: Working with extension tubes, aperture query  (Read 1211 times)

Offline akshayeakki

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Working with extension tubes, aperture query
« on: January 04, 2014, 06:39:28 PM »
Hello friends- I recently bought auto extension tubes for Nikon (for body- D5100). I'm facing issues with images being washed out when I use all 3 tubes (36mm, 20mm and 12mm) and overexposed in Aperture Priority mode most of the times, can you give me tips for controlling the exposure when using all 3 tubes?
Another thing is -what aperture should I click on for not getting too shallow DOF? I notice even f13-16 has very litlle DOF when all the 3 tubes are combined. Would increasing f value to say f22 would reduce the image quality? Other than these issues please suggest me some tips and tricks while using the extension tubes for macros. thanks   
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Offline theqca

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Re: Working with extension tubes, aperture query
« Reply #1 on: January 04, 2014, 07:16:47 PM »
Some tips in random order..

1 - don't stack tubes unless u need that level of magnification. At times the pic looks better with a moderate amount of magnification too

2 - u need external flash for a lot of high magnification pics. If don't have that use a toothpaste tube and put it on top of ur pop up flash so ur able to get some direction to the light in a manner where it comes towards the end of the lens. Google this trick for diagrams / details.

3 - learn to focus stack..

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Offline theqca

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Re: Working with extension tubes, aperture query
« Reply #2 on: January 04, 2014, 07:19:04 PM »
One more.. Shoot at around f11 and get the camera sensor parallel to the subject... Don't reduce the aperture.. Work on technique instead.

Can u post a few sample shots of the pics ur having an issue with pls?
Nikon FM(black), Nikon FG, Nikon D700, Nikon FM(silver), Nikon FM10, Pentax Spotmatic, Zenith TTL, Minox Wetzlar, Agfa Optima III, Yashica & Rollei rangefinders etc

28mm 2.8, 70-300vr, 200mm f4, 50mm 1.4, 55mm 2.8 macro, 50mm 1.8, 16mm 2.8, 70-210 f4 macro, Lensbaby, Helios 44 f2, 90mm macro, etc

Offline akshayeakki

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Re: Working with extension tubes, aperture query
« Reply #3 on: January 04, 2014, 07:40:02 PM »
thank you very much for the reply :) I will certainly keep this in mind next time.

one more question- will the same f number (say f11) have the same effect on exposure when the lens is coupled with whole set or coupled with only one tube?
The eye should learn to listen before it looks - Robert Frank

Offline dashillol

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Re: Working with extension tubes, aperture query
« Reply #4 on: January 06, 2014, 05:09:01 PM »
Dont stack all 3 tubes together. Majority of the time, it reduces FL to a negative one. Try with 2nd or 3rd singularly or in combination. Move your camera back and forth slowly to get the correct focus. Keep the subject parallel to sensor plate. Another personal observation is, ETs work better with lower FL lens.  :)
« Last Edit: January 06, 2014, 05:12:58 PM by dashillol »
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Offline hayath

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Re: Working with extension tubes, aperture query
« Reply #5 on: January 06, 2014, 07:07:39 PM »
Adding onto the excellent tips so far.

1. Try dialing in negative exposure compensation
2. Check the inners of the tubes, if they're reflective you could be losing a lot of contrast - ideally the inners shouldn't reflect any light

Quote
one more question- will the same f number (say f11) have the same effect on exposure when the lens is coupled with whole set or coupled with only one tube?

It surely will increase your "effective" aperture and overall exposure - since the extension is being increased with light loss

I know it can be daunting at the outset, and in fact easy to stack all 3 ETs. Try working your way up by starting with one/two at max

PS: Which lens are you using these ETs with?

Cheers,
Hayath

Offline akshayeakki

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Re: Working with extension tubes, aperture query
« Reply #6 on: January 07, 2014, 09:35:18 PM »
PS: Which lens are you using these ETs with?

Mostly I use Nikkor 50mm 1.8D, tried using sigma 70-300 too a few times
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Offline hayath

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Re: Working with extension tubes, aperture query
« Reply #7 on: January 08, 2014, 12:26:04 PM »
PS: Which lens are you using these ETs with?

Mostly I use Nikkor 50mm 1.8D, tried using sigma 70-300 too a few times

With the 50mm you will be going over 1:1. Try out lower mags and work your way up :)
figuring out lighting is key

Offline theqca

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Re: Working with extension tubes, aperture query
« Reply #8 on: January 08, 2014, 11:17:03 PM »
Another personal observation is, ETs work better with lower FL lens.  :)

A small correction - they wont work "better" with a shorter focal length...Ronnie Gaubert was a nature photographer who is famous for his technical accuracy and attention to detail in macros and he shot extensively with ET's mounted on a 70-200 and 300mm lens.
Nikon FM(black), Nikon FG, Nikon D700, Nikon FM(silver), Nikon FM10, Pentax Spotmatic, Zenith TTL, Minox Wetzlar, Agfa Optima III, Yashica & Rollei rangefinders etc

28mm 2.8, 70-300vr, 200mm f4, 50mm 1.4, 55mm 2.8 macro, 50mm 1.8, 16mm 2.8, 70-210 f4 macro, Lensbaby, Helios 44 f2, 90mm macro, etc