Here's what I have.
K-5, DFA 100mm Macro, a p=ttl flash, a cheap led ring flash, 3 cheap extension tubes and the Prospec 2x Tele-Converter. I am thinking about getting magic arm, oh i have a p-ttl 3ft poloroid flash extension cable and a diffuser for the flash too.

I have to be honest I dont know how to use the extension tubes, and I am afraid ill kill sharpness with the teleconverter (my only real experience with it was a short lived experiment using a M 200mm f4). I tried the teleconverter with an otherwise sharp 200mm out the world and the photos were terribly unsharp. though in retrospec I was using catch in focus to try and shoot birds in motion with no flash, which I would love to do, but I can never seem to get great shots of.

Anyway back to macro, I want to get closer than the shots I have attached and still have great sharpness. How should I go about it.

I have a sigma 28mm f1.7 macro and 18-50 f2.8 macro as well but I figure the best macro lens I have is the DFA 100mm.

Suggestions please.

[amoringello]

Teleconverters add glass and affect sharpness a lot.
Extension tubes are just that. They pull the lens away from the sensor plan enlarging the image cast upon it.. in effect magnifying the image.
In the end you don't change the DOF but you loose a little exposure.
If your lens isn't really sharp to begin with, its deficiencies (un-sharpness) will also be magnified.

Dunno if you're meaning to get sharper images, or more depth of field to that more of the image is in focus.
If you want greater depth of field, you'll need a smaller aperture than f/4.0 (i.e. f/16). But this will require more exposure. i.e. slower shutter speed or use o flash.
If smaller aperture doesn't do enough, you night need to take multiple photos and find doe software that allows you to do "focus stacking" to put them together to create a large area being in focus.

One downside to your equipment, is you need a real Macro lens. I'm assuming the 100mm is a macro lens.
Dunno about the 28mm f/1.7. But the 18-50 is not really a macro lens.
Although turn the 28mm f1.7 around and it might make a great macro! (just need to hold the lens steady or get a reversing ring to mount it to your camera that way)

[baro-nite]

Depth of field (DOF) gets thinner as you focus closer. So while f/5.6 is probably a good sharp aperture for this lens, the DOF is very thin at this magnification. Try stopping down more.

When you say you want to get closer, are you saying these are at minimum focus distance (MFD)? Anyway, I suspect your cheap extension tubes don't have the A contacts (6 or 7 metal nubs similar to what's on the camera lens mount), in which case you'll need a lens with an aperture ring. Is your DFA100 the older version with aperture ring?

[bluestringer]

As the others have said, you need more DOF, like f8-f16, and you need light. You can put the 100mm macro in front of a 36mm tube and get close. But you need to use the flash, and have some kind of diffuser with it. Also forget AF, you'll get better results using manual focus for macro shots. I use the catch-in focus feature and get good results with it. If you have the cheap extensions tubes with no aperture control, that will deter you from getting good shots. I suggest either getting tubes with aperture control, or getting a cheap 2x tele-converter and remove the glass, that will give you a nice 25mm tube with aperture control.

[dappercorpmonkey]

Thanks for all of the tips. Sorry for not clearly stating the intended goal. By closer I meant that I wanted more magnification, without sacrificing image quality. Increased DOF would be nice as well. My DFA 100mm Macro does have an aperture ring, and my cheap tubes do not have pins. I am unclear as to how many stops of light you lose with the tubes.

[rbefly]

Hello dappercorpmonkey, welcome to the Forum!
I believe the advice you've gotten so far is good, stopping down is the only way to get more DoF, which of course reduces shutter speed and/or raises ISO.
But judging from the photos I've seen posted here by other users, you own one of the sharpest, best macro lenses Pentax (or anyone else) has ever produced, the D FA 100mm f/2.8.
So, I'm guessing the the problem isn't gear, it's technique. Hope you won't be insulted, but here goes.
Did you use a tripod? My guess is no, and both photos appear a tiny bit 'fuzzy' because (again, I'm guessing) camera shake. Especially # 2.
It could also be 'wind shake'.
For now, try this experiment. Take a small, finely-detailed object and place it in normal sunlight. Photograph it at 1/160s, handheld. Set up a tripod for the exact same photo and photograph the same object at 1/160s, using a cable release, 2-second delay (for mirror lock-up) after careful auto/manual focusing.
If the second photo is even a tiny bit sharper, well, there you go!
While you have the setup, stop down to f/11 (in AV and ISO 100) and use a white posterboard (or reflector) to bounce light onto the shadow side. With the cable release or clicker, move the board around and keep clicking. Each shot will tell you more about lighting than I ever could.
Now, try your flash at 1/4 power on a cord, here, there, over, under.
Good macro isn't a single big skill or one piece of gear. It's a lot of little techniques, practice, work and hopefully, some artistry.
Stable camera platform, right settings and dead-on focus, control the light, angle, POV and background.
End of lecture.
Ron

[OregonJim]

I am unclear as to how many stops of light you lose with the tubes.

It depends on the length of the tubes. Square the distance from the sensor to the back of the lens (mounted on the tubes) and divide that by the square of the focal length to get the exposure factor. E.G., 54mm distance with a 28mm lens is 54^2 / 28^2 = 3.7 (which is almost 2 stops of light).

[Nass]

If the 28 has manual f stops you can reverse the 28 onto the 100
Or try using the 100 with extension tubes
Both cases you'll want to probably use flash and have a decent diffuser
Relevant links:

Stacking lenses for extreme macro
Spreading the light with extreme macro diffusion

[pericombobulation]

If you just want more magnification than you have now, why not try a macro adapter (diopter) which screws on to the filter ring? These are pretty inexpensive and they don't adversely affect image quality much at all. And your auto aperture will work fine. A +10 diopter will get you significantly closer than you're getting now. Of course then you'll have to deal with razor thin DOF, but that's another topic, and any macro setup you choose will have that problem anyway.

[dappercorpmonkey]

It depends on the length of the tubes. Square the distance from the sensor to the back of the lens (mounted on the tubes) and divide that by the square of the focal length to get the exposure factor. E.G., 54mm distance with a 28mm lens is 54^2 / 28^2 = 3.7 (which is almost 2 stops of light).

Do you need to know the distance to the sensor inside the body as well there? So I take my 100mm lens^2/ the tubes +body space?^2

[NicoleC]

For increased DOF, you can also use focus stacking to take multiple images and then blend them in Photoshop (etc). This allows you to keep a nice bokeh in the background with greater DOF on the subject matter. This photo from yesterday, for example, is a composite of 4 images. I wanted the bloom to stand out without the distraction of the plants in the background being in focus.

[bluestringer]

Do you need to know the distance to the sensor inside the body as well there? So I take my 100mm lens^2/ the tubes +body space?^2

You are making it too complicated. Don't worry about how many stops you lose with tubes, just put your camera on X, put your flash in auto, check the flash distance for the ISO you are using, set aperture to that value (probably f8-f16) and shoot. You may need to adjust the aperture a stop or 2 either way to get what you want.

If you are not using a flash, just set the camera to manual, set the aperture to f8 to start, use the green button to meter. If the shutter speed is too low, reset the aperture until you get a higher speed.

[OregonJim]

Do you need to know the distance to the sensor inside the body as well there? So I take my 100mm lens^2/ the tubes +body space?^2

Yes, but it's marked right on your camera body. It's the little circle symbol with a line through it.

[carrrlangas]

K-5+DFA100+Flash = everything in manual mode.
I´d mount the DFA100, camera mode Manual and mount the Flash in manual mode too. f/16, 1/180sec (maximum sync speed) and ISO200 to start. Flash power output to 1/2 for starters. Play with the flash power and ISO values until you get good exposure at the distances you are shooting. Don´t worry about ambient light, it won´t contribute at this f-stop and shutter speed. if K-5 AF can´t lock, switch to liveview and manual focus.

[old4570]

Hmmm , rig listed should take fantastic photos ...

Practice practice and more practice ...

1/ Let there be light .
You need to get light , at the angle you want , onto the subject you are photographing .. There are lots of ways of doing this , check out youtube ....

2/ Aperture .
The closer you get to your subject , the less depth of field you have , so you need a smaller aperture setting ( higher F stop ) , how high will your lens go . ( aim for the highest possible F stop )

3/ Shutter speed
You must maintain a decent shutter speed OR be seriously steady ( tripod steady )

4/ How close do you want to get ?
1:1 is rather good , but for those insane in your face shots you need better than 1:1 , and possibly a bigger lens .
A decent Macro teleconverter might be on the cards .. A good one will not rob you of much quality , but a poor one will !
I have a few myself , and they really help expand your options .
Or get one of those lens adapters that reverses a lens ( backwards ) , buy a cheap lens ( still decent ) , to use as a dedicated backward lens .
So many options , so many ways of doing it ( Macro ) , you just need find what works for you .