[yeatzee]

If I am using a macro lens + extension tubes without electrical contacts, do I set the SR to the macro (105mm) or the macro + extension tubes? I just set it to the macro but one of my Nikon buddies told me to set it to both the macro and extension tubes. Which is it?

Thanks

[brecklundin]

The tubes do not change the optics. They only move the lens farther away from the sensor. Not sure of that actually would be considered a change in focal length. But I would say try it and find out? That will give you a better idea. I am more of a try it and know sort of guy...even is someone says yea or nay unless you try it ya never know for certain.

[stevebrot]

This going to sound a bit abrupt, but with extension tubes you should use a tripod and turn SR off.

Reasons:

• SR is not particularly effective at higher reproduction ratios
• Ditto for hand holding
• SR can introduce softness when used with a tripod

If you must use it, I think you probably would use the actual focal length. (Anyone else is free to contradict me on this...)

Steve

[brecklundin]

This going to sound a bit abrupt, but with extension tubes you should use a tripod and turn SR off.

Reasons:

• SR is not particularly effective at higher reproduction ratios
• Ditto for hand holding
• SR can introduce softness when used with a tripod

If you must use it, I think you probably would use the actual focal length. (Anyone else is free to contradict me on this...)

Steve

Sorry gotta call you on the whole "you should be using a tripod" comment. Why and who 'sez'? would be my question.

There is no 100% "rule" only opinion in this case. In fact macro shooters I know, shoot hand held in the field... If you have ever shot at 3x or above you know it can be as if shooting at 300mm or longer handheld even if the subject fills the frame. SR will usually help in these situations but one needs to try and see which is best for the individual.

As mentioned, only personal testing will tell each person whether SR will help in their unique situation or not. If you depend on a tripod for macro shooting, it will significantly reduce your shot opportunites. One is better off learning good technique to hand hold your macro shots in the field. In a controlled environment it's a coin toss.

[stevebrot]

Sorry gotta call you on the whole "you should be using a tripod" comment. Why and who 'sez'? would be my question.

There is no 100% "rule" only opinion in this case. In fact macro shooters I know, shoot hand held in the field... If you have ever shot at 3x or above you know it can be as if shooting at 300mm or longer handheld even if the subject fills the frame. SR will usually help in these situations but one needs to try and see which is best for the individual.

As mentioned, only personal testing will tell each person whether SR will help in their unique situation or not. If you depend on a tripod for macro shooting, it will significantly reduce your shot opportunites. One is better off learning good technique to hand hold your macro shots in the field. In a controlled environment it's a coin toss.

No problem being "called". My advice is based on personal experience with the gear I own. For anyone else, your results may vary. To answer your call specifically:

• Why? So that you can get sharp pictures
• Who sez? Me

Simply put, my experience is that I find it difficult to get adequately sharp macro without camera support. I tried using SR, but found it to not be affective at reproduction ratios greater than 1:3. Having said that, I should qualify by saying that I don't have a real good flash setup so it is entirely possible that SR + fast synch + a good ring or bounce flash might allow for hand-holdable macro.

Having said my piece, I will extend a challenge. Are you willing to submit a series of shots, SR on/off hand-held at 1:3, 1:2, 1:1, 2:1, and 3:1? I would suggest a centimeter ruler with millimeter gradations as a subject with a postage stamp or currency occupying the remainder of the field.

Steve

BTW...I am curious as to how one handles limited DOF and fine focus when hand holding at 3:1 or even 1:1 for that matter?

[Wheatfield]

No problem being "called". My advice is based on personal experience with the gear I own. For anyone else, your results may vary. To answer your call specifically:

• Why? So that you can get sharp pictures
• Who sez? Me

Simply put, my experience is that I find it difficult to get adequately sharp macro without camera support. I tried using SR, but found it to not be affective at reproduction ratios greater than 1:3. Having said that, I should qualify by saying that I don't have a real good flash setup so it is entirely possible that SR + fast synch + a good ring or bounce flash might allow for hand-holdable macro.

Having said my piece, I will extend a challenge. Are you willing to submit a series of shots, SR on/off hand-held at 1:3, 1:2, 1:1, 2:1, and 3:1? I would suggest a centimeter ruler with millimeter gradations as a subject with a postage stamp or currency occupying the remainder of the field.

Steve

BTW...I am curious as to how one handles limited DOF and fine focus when hand holding at 3:1 or even 1:1 for that matter?

Consider that even if there is no "100% rule", there is pretty overwhelming evidence that all else being equal, using a quality tripod under the camera will give a sharper picture than a hand held exposure, and this just gets more true at higher magnifications.
A 1:1 macro lens with any extension tubes to increase magnification beyond it's native limit is going to be giving magnifications that are well nigh impossible to handhold.

[yeatzee]

I much prefer handheld shots because my subjects never stay in one place long enough to make a tripod practical. Check my post in the post your pictures section to see the sharp results I got hand held. Its under the name extension tubes

[brecklundin]

Consider that even if there is no "100% rule", there is pretty overwhelming evidence that all else being equal, using a quality tripod under the camera will give a sharper picture than a hand held exposure, and this just gets more true at higher magnifications.
A 1:1 macro lens with any extension tubes to increase magnification beyond it's native limit is going to be giving magnifications that are well nigh impossible to handhold.

I don't see how you are spinning this into that I was saying shots taken w/o a tripod are less sharp than hand held...if something I wrote gave you that mistaken impression sorry for that...

Taking a lens beyond it's native mag using tubes, which btw are 100% air inside, has no effect on IQ and that also is proven out by millions of example shots anywhere you care to look. It may make flaws in a given lens more apparent just as cropping will, but it does not reduce the actual IQ only the apparent IQ depending on the lens.

Sounds like ya don't have much practice with true macro. I would offer as an example these shots by one of my favorite macro shooters:

Insect/bug Macros 2009 - a set on Flickr

These days he shoots almost exclusively with an MP-E 65mm anywhere from 1x-5x...hand held...but he is an amazing shooter and is by no means the rule. Not a lot of us can shoot hand held at more then 3x and get the keeper rate Brian does. I have yet to see a shot where he uses more than his quite, ummmmm, unusual and unique "bean pole" technique...funniest and simplest trick you can imagine to provide fast adjustment as well as a fair bit of support when needed. Just a cheap plastic garden "stake/pole" held between your hand and the camera body. If I can find the example shots he posted I'll add the link.

Many things to consider when shooting macro including to remember the standard methods of shutter speed=1/focal-length but remember to include the crop factor as well as take into consideration the mag ratio, flash, etc...but it is very possible WITH PRACTICE patience and proper planing, to shoot high mag shots hand held. A solid grasp of DOF is also a must and still struggle with it at times myself. By right now since there is nothing like an MPE-65mm for Pentax, my macro shooting is on hold even though I have and love the 35ltd macro. The closest I could come would be to use an auto-bellows and I find them awkward to manage.

I had fun with a Sigma 180mm Macro and a reversed 24-60mm f2.8 that gave me 3x - 7.5x and shot every one hand held. You won't have a high keeper rate but it can be done with success. It was insane but it sure was fun!!

Tripods and macro in the field are pretty difficult to coordinate and you will miss more shots, by a wide margin, than you lose by hand holding at any mag ratio.

And SR on a tripod is always going to depend on the tripod too...but certainly on a solid base SR could induce some vibrations and blur. But as I mentioned it is not a hard fast rule. And that is my point...only practice and experimentation.

And as to the OP's question, I have looked around and given the way the Pentax SR works, it needs to know the focal length of the lens, so I would have to guess the best thing to do is try setting the focal length manually at the lense's actual focal length then what it would be taking the mag ratio into account...mag ratio = 1 + (focal length of lens/length of tubes) so a 50mm macro with 50mm of tubes vice a 2x (2:1) ratio so try manually entering first 50mm, take a few shots, then enter 100mm and take the same shots and go from there...the important factor for the using the Pentax system is to register the right focal length in the body. On the K20D it's the last item on the 2nd screen of the Rec. Mode Menu and I assume it is enabled when the lens is not reporting a focal length, but that can be looked up in the manual.

[brecklundin]

I much prefer handheld shots because my subjects never stay in one place long enough to make a tripod practical. Check my post in the post your pictures section to see the sharp results I got hand held. Its under the name extension tubes

Love the shot...very nice

You might like to see Brian's "Bean Pole" in action...wait, that sounds wrong...but, anyway...

Brian's Bean Pole Technique

[stevebrot]

...You might like to see Brian's "Bean Pole" in action...wait, that sounds wrong...but, anyway...

Brian's Bean Pole Technique

Cool technique! I have a bunch of those in my garden and will have to give it a try.

Steve

[stevebrot]

...mag ratio = 1 + (focal length of lens/length of tubes)...

There is something wrong with this formula. My experience has been that the longer the focal length of the lens, the less magnification you get from a given extension. The formulas I have seen look something more like this:

Magnification = (tube + focusing extension)/focal length

For the OP's 105mm macro, he would need 210mm of tubes to get 3:1. With my 50mm Macro, I would get the same magnification with only 100mm of extension.

Steve

[brecklundin]

There is something wrong with this formula. Generally, the longer the focal length of the lens, the less magnification you get from a given extension. The formulas I have seen look something more like this:

Magnification = (tube + focusing extension)/focal length

Steve

Yeah, I wrote the equation for reversing using just two lenses by mistake...d'oh!!

The real equation using tubes is a bit more complicated but your's is close:

Multiplication Factor Using Tubes

MF = (External Lens Extension / Focal Length) + Magnification setting on primary lens

So, say you have a 100mm macro and 50mm of tubes with the lens set to 1.5x (easy numbers to use...hey, I'm lazy!! hehehe)

MF = (50mm/100mm) + 1.5 = 0.5 + 1.5 = 2.0x or 2:1

Thanks for catching the goof on my part...do you happen to have any info on equations to calculate the effects on the min distance from subject? I have always had to do it using the by-golly-or-by-gosh method...

[stevebrot]

I much prefer handheld shots because my subjects never stay in one place long enough to make a tripod practical. Check my post in the post your pictures section to see the sharp results I got hand held. Its under the name extension tubes

https://www.pentaxforums.com/forums/post-your-photos/67706-extension-tubes.html

Nice macros! How much extension did you add? I am curious how you managed the focus with the lens set at 1:1. Do you put the camera to eye and just keep moving closer until the subject is in focus?

Steve

[stevebrot]

Yeah, I wrote the equation for reversing using just two lenses by mistake...d'oh!!

The real equation using tubes is a bit more complicated but your's is close:

Multiplication Factor Using Tubes

MF = (External Lens Extension / Focal Length) + Magnification setting on primary lens

So, say you have a 100mm macro and 50mm of tubes with the lens set to 1.5x (easy numbers to use...hey, I'm lazy!! hehehe)

MF = (50mm/100mm) + 1.5 = 0.5 + 1.5 = 2.0x or 2:1

Thanks for catching the goof on my part...do you happen to have any info on equations to calculate the effects on the min distance from subject? I have always had to do it using the by-golly-or-by-gosh method...

Yes, that looks quite a bit better. No, I don't have a formula for calculating the working distance. All I know is that it is never far enough!

Steve

[brecklundin]

Yeah, I wrote the equation for reversing using just two lenses by mistake...d'oh!!

The real equation using tubes is a bit more complicated but yours is close:

Multiplication Factor Using Tubes

MF = (External Lens Extension / Focal Length) + Magnification setting on primary lens

So, say you have a 100mm macro and 50mm of tubes with the lens set to 1.5x (easy numbers to use...hey, I'm lazy!! hehehe)

MF = (50mm/100mm) + 1.5 = 0.5 + 1.5 = 2.0x or 2:1

Thanks for catching the goof on my part...do you happen to have any info on equations to calculate the effects on the min distance from subject? I have always had to do it using the by-golly-or-by-gosh method...

ahhhh, crap I made a silly error there too...using a setting for the mag ration for the primary lens would NOT be 1.5 it would be 0.5 (Seriously...I knew that...unless using something like the MPE-65 that is...) so the numbers would work out like this:

MF = (50mm/100mm) + 0.5x = 0.5 + 0.5x = 1.0x or a 1:1 ratio. Sigh, you would cringe is you knew what my degrees are in...but arithmetic is my WORST place for errors and constantly needs checking...turn me loose with solving systems, especially non-linear dynamic systems, and we are good, ask me to multiply (-1)(-1) and I will be 50/50 on writing down -1 instead of the correct value of 1....also always check the signs on my exponents for the same reason.

Yes, that looks quite a bit better. No, I don't have a formula for calculating the working distance. All I know is that it is never far enough!

Steve

Yup, kinda helps to use the correct equation...hehehe....thanks for letting me know you haven't come across an equation for the distance change. Younger brains than mine can probably develop one...but not only do optics (well, anything to do with physics) baffle me, but applied mathematics is NOT my friend...theoretical, you betcha...

BTW, at times I am mildly dyslexic when typing so never worry about point out these things to me...I am used to being wrong, heck it has become a way of life!!

Even hear the "assume a spherical chicken" joke?