Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-27-2012, 05:10 PM   #1
Pentaxian
littledrawe's Avatar

Join Date: Jan 2010
Location: Red Rock
Photos: Gallery | Albums
Posts: 2,454
Extension tube question?

I was using my tokina 60-120mm lens to take some pictures of things I wanted to sell. I used the on camera flash because I was lazy but wanted to brighten things up. So, I was at 1/180s 400iso f11-f16. I wanted to reduce the minimum focus distance to get in a little closer so I broke out my extension tubes which I have never used before and put a section inbetween the camera and the lens and went back to taking pictures.
Now,on-camera flash aperture around f11-f16 1/180s and the first picture I took with the extension tubes was all white, totally blown out. I went to f22 and same thing. I closed the flash and sure enough it was under exposed but not horribly.
I've always heard that extension tubes add a stop or 2 (RioRico said they "eat light") so why would these pictures have been so much brighter after the extension tubes then before?

Here is a picture of the tubes if it helps



03-27-2012, 05:23 PM   #2
Site Supporter
Chaos_Realm's Avatar

Join Date: Feb 2011
Location: Melbourne, Australia
Photos: Gallery | Albums
Posts: 1,251
what mode do you have your camera on?
I vaguely remember there is a mode that if it doesn't have contacts, then it shoots the lens wide-open. I dont have my camera near-by to check but it might be something to consider.
03-27-2012, 05:25 PM   #3
Senior Member




Join Date: Dec 2009
Location: europe
Posts: 148
Hi Littledrawe,

Nice to see your post

I actually have exactly the same extension tubes, found second hands for few bucks recently, and also had trouble in making a proper macro picture.

I used a manual facus pentax 50mm /1.7 A lens for that, and I noticed that I can not set the aperture (manually on the lens or via the camera in Av mode) as required.

When mounting the tube on the lens, everything looks ok. Moving manually the small metallic "finger" (what's the name in english?) would trigger the diaphragm properly.

But when I mount the lens+ tube on the K5, while turning to fix it, I can see the diaphrag opening as wide as possible (so it sticks f1.7) and nothing can be done to close it.

I guess that what you have too, overexposure because your lens is actually opened at its maximum and not at the f16 value you set.

If somebody knows how to fix that
03-27-2012, 05:27 PM   #4
Veteran Member
joe.penn's Avatar

Join Date: Mar 2011
Location: Maryland (Right Outside Washington DC)
Photos: Gallery | Albums
Posts: 2,902
You need to "foil" the contacts of the body to enable stop down metering/shooting with those tubes. The reason why your snaps were blown out was because every snap was shot wide open...


Last edited by joe.penn; 03-27-2012 at 05:34 PM.
03-27-2012, 05:32 PM   #5
Veteran Member
joe.penn's Avatar

Join Date: Mar 2011
Location: Maryland (Right Outside Washington DC)
Photos: Gallery | Albums
Posts: 2,902
Searched for a reference for a pic but can't find one - when I say "foil", I mean "aluminum foil" - take a small piece and use to short the contacts on the body, put the foil on the contacts while you are attaching the extension tubes, once the extension tubes are attached the foil will short the contacts and the lens will "stop down" in hyper manual mode as it should.

FYR: You can always sand down the flange on the tubes to the bare metal, then you won't need the foil...
03-27-2012, 05:40 PM   #6
Site Supporter
mattt's Avatar

Join Date: Feb 2011
Location: Niagara
Photos: Gallery | Albums
Posts: 2,805
If the Tokina lens supports P-TTL / TTL metering you are probably finding that with the extension tube you must shoot in full manual. The classic tubes you have shown there do not support metering (no electrical connections to communicate to the camera body with. Given that the flash is extremely close, and in full manual mode the flash will default to 100% power you will need to use off camera flash, and activate it using a bounce card or similar. I've done similar on a number of occassions....

Shot with DA 21 Ltd on Asahi Pentax Extension Tube #1 with AF 540 FGZ camera Right at 1/4 power triggered with the pop up flash & bounce card.
03-27-2012, 06:22 PM   #7
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
Unless you are using an *istD and a flash that supports TTL flash as opposed to P-TTL the are two things that will happen, the lens will not stop down and the flash will go at full power.
03-27-2012, 06:39 PM   #8
Loyal Site Supporter
monochrome's Avatar

Join Date: Mar 2008
Location: Kirkwood (St. Louis) MO
Photos: Gallery | Albums
Posts: 20,423
QuoteOriginally posted by Lowell Goudge Quote
Unless you are using an *istD and a flash that supports TTL flash as opposed to P-TTL the are two things that will happen, the lens will not stop down and the flash will go at full power.
Just a quick question. If I want to do similar with a K10D and Pentax K Auto Extension Tubes (have the aperture lever) can I use an AF280T and shoot in TTL mode?

03-27-2012, 09:58 PM   #9
Veteran Member
Philoslothical's Avatar

Join Date: May 2011
Posts: 1,723
QuoteOriginally posted by joe.penn Quote
FYR: You can always sand down the flange on the tubes to the bare metal, then you won't need the foil...
This works better for me. Less can go wrong, and it's permanent. Fine silica sandpaper is the way to go, just buff off the paint with it until you get a reliable contact. Be sure to clean the surfaces well before mounting it on your camera - I'd hate to get that fine paint dust on the sensor.
03-27-2012, 11:03 PM   #10
Pentaxian




Join Date: Feb 2009
Location: Alameda, CA
Posts: 3,198
QuoteOriginally posted by monochrome Quote
Just a quick question. If I want to do similar with a K10D and Pentax K Auto Extension Tubes (have the aperture lever) can I use an AF280T and shoot in TTL mode?
K10D does not support TTL mode, with or without extension tubes.

The Pentax K Auto Extension Tubes don't have A contacts. You need a lens with aperture ring and set the aperture ring of the lens at a non-A setting (if A setting exists) and treat the lens + tube(s) combo as a manual lens.

Also, note that the actual aperture is not the setting of the aperture ring of the lens. The actual aperture is slower, how much slower depends on the length of the tube(s) and the focal length of the lens.
03-28-2012, 08:00 AM   #11
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
QuoteOriginally posted by monochrome Quote
Just a quick question. If I want to do similar with a K10D and Pentax K Auto Extension Tubes (have the aperture lever) can I use an AF280T and shoot in TTL mode?
As SOldBear said, the K10D does not support TTL flash.

The only cameras that support TTL flash are the *istD series, but I am not sure about the DL .

There is a real confusion presently about "Auto Extension Tubes" because in the 1970's and early 1980's auto extension tubes and auto aperture referred to the aperture being held open for focusing and / or metering and stopping down to shoot. Auto extension tubes were ones that had the aperture activation lever integrated into them.

The camera body "Auto Aperture" or A setting on lenses came about later, and this is what confuses people. To use extension tubes and retain camera body controlled aperture you need KA mount extension tubes with contacts.

This is why I keep my *istD. In reality, there is not that much gained when doing macro between say 6 and 10MP but the ability to control flash is very important, and also as SOldBear noted, there can be some real exposure issues with macro, when adding extension tubes. In this application the older TTL metering works better because it works based upon the actual light hitting the sensor.
03-29-2012, 10:57 PM   #12
Pentaxian
littledrawe's Avatar

Join Date: Jan 2010
Location: Red Rock
Photos: Gallery | Albums
Posts: 2,454
Original Poster
So, I need to get down to bare metal on the mount of the tubes to prevent the camera from defaulting to MAX aperture on every shot and by sanding the mount of the tubes the camera will shoot at the aperture I have the lens set at??
03-30-2012, 03:53 AM   #13
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
QuoteOriginally posted by littledrawe Quote
So, I need to get down to bare metal on the mount of the tubes to prevent the camera from defaulting to MAX aperture on every shot and by sanding the mount of the tubes the camera will shoot at the aperture I have the lens set at??
No, this will not work. You need a pin in location 3 (3rd pin from the lens locking pin) to tell the camera it is an A lens, you will note that the body side contact is recessed. Then younwould need to drill the pattern in the extension tube to correspond to maximum and minimum aperture. The base of your lens is conducting, and will therefore short pin 7 giving you focus confirmation already

Unless you really know what to do, there is not an easy conversion to make this an auto aperture (I.e. A ) set of tubes. You are stuck with manual mode on the camera and manual flash calculations
03-30-2012, 10:54 AM   #14
Veteran Member
Philoslothical's Avatar

Join Date: May 2011
Posts: 1,723
Lowell, he's not trying to get A series performance, he's trying to get proper stop down metering and M series performance when shooting (the lens should stop down briefly when taking the shot). You can see from the pic that he has "A type" tubes, as in mechanical aperture linkage. If it's not stopping down the lens to the aperture he sets on the lens when shooting, he needs to short the sixth contact so the camera knows a lens is attached. It's the same with the K-r, but it does contradict what someone said in another thread about their K-7. It can't hurt to try.

Thing is, it shouldn't be necessary for shooting, only for metering. So, maybe there's something else going on.
03-30-2012, 12:55 PM   #15
Pentaxian
littledrawe's Avatar

Join Date: Jan 2010
Location: Red Rock
Photos: Gallery | Albums
Posts: 2,454
Original Poster
QuoteOriginally posted by Philoslothical Quote
Lowell, he's not trying to get A series performance, he's trying to get proper stop down metering and M series performance when shooting (the lens should stop down briefly when taking the shot).
I don't really want transform these and add contacts. I just don't want the camera to default to f2.5 on every shot.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, extension, extension tube, flash, k-mount, lens, pentax lens, picture, pictures, slr lens, tubes
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
auto extension tube question Classico Pentax SLR Lens Discussion 16 01-20-2012 09:01 AM
Extension Tube Question Barron Troubleshooting and Beginner Help 5 06-22-2011 05:59 PM
m42 extension tube question gokenin Pentax SLR Lens Discussion 4 07-23-2010 01:54 PM
Extension Tube Question eccs19 Pentax Camera and Field Accessories 3 01-29-2009 03:28 PM
Extension Tube Question twilli53 Pentax SLR Lens Discussion 4 03-04-2007 07:22 AM



All times are GMT -7. The time now is 05:35 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top