Macro help

[Jonathan Allen]

I am going to have a go at macro photography and I have never done it before. If I use extension tubes will I lose light and if so what's the best way to adjust the exposure.
I am going to be using a Pentax Spotmatic and the meter isn't that reliable.
If I was to use my canon G15 in macro mode and take a reading from that will it be the same exposure with the lens and extension tubes on the Pentax.

Thanks in advance for any help you can give.

 

[Julian de'Courcy]

As for extension tubes, as they do not have any glass and they are a simple tube, exposure aught too be unaltered. I have a couple of sets of tubes and find them useful over my macro lenses as I can put various lenses onto them.
I have in the past prior too getting tubes put kitchen roll centres or plastic pipe taped to the camera and lens which worked fine indoors. A bit fiddly but does work.

 

[Jonathan Allen]

Thanks Julian.
I am going to have a go next week with the roll of film i have loaded. I am going to use a GX8R ring flash as well wth the mark shots.
I am also going to use the GX8R on some close up portraits to see what look i can get with a low powered flash. It will be interesting to see what the GX8R can do in regards the portraits shots and if it will be effective as a fill too when using my other lights.

 

[Ian Grant]

How unreliable is the meter ? I was using my Spotmatic F with extension tubes earlier this year with great results, I quite like using my 100mm f2.8 SMC Takumar with them.

When I first used extension tubes it was with a Zenit E, there was a list of exposure factors for use with them. There may be something in the Keppler, Pentax Way, book, worth getting if you haven't already got a copy.

Ian

 

[Jonathan Allen]

Thanks Ian. I'll look for a copy.
The meter is really bad. I think it needs a service and put right.