Beginning macro shots

photosmart42 · Post by **photosmart42** » Fri Jan 22, 2010 7:54 pm

Posted these on another forum as well, but I might as well solicit feedback as well. There are not my first macro shots, but they're certainly the most technically challenging ones so far. Actually had to break out the tripod and flash for these.

Finally got my 52mm reverse adapter, so I took some quick macro shots with my 20mm/1.7 reversed (f/10, ISO100, 1/160 shutter speed, 4:3) off my GH1. Tripod mounted + macro focusing rail. Lighting provided by desk lamp + off-camera Vivitar 285 at 1/16 power bounced off white envelope I had on my desk. Rubix cube provided raised platform for the 'specimens' =). Here's what came out:

Lens cap:

Pencil shavings:

pierre · Post by **pierre** » Sat Jan 23, 2010 4:59 am

Well done !!

lauriek · Post by **lauriek** » Sat Jan 23, 2010 5:41 am

Hmm. 20mm/1.7mm lens, Lens cap says "Lu" (...mix?) - This must be one of the micro 4/3 cams, which one are you shooting with? (Sorry I just re-read and saw it's a GH1, no need to answer!)

Shots look technically quite nice. Not sure about the dof. Can you stop the lens down when it's reversed? (I notice you mention shot at f10, but does the lens actually stop down when not attached directly to the camera?)

A good start! I for one look forward very much to seeing what you can do with this camera!

ChrisR · Post by **ChrisR** » Sat Jan 23, 2010 6:11 am

PIerre, welcome. You'll get a lot of support and encouragement on this forum, so allow me to toss some negativeish comments in! Hope you find them constructive.

You're mixing your desk lamp (filament bulb??) with flash. Flash is approximately = daylight, but not the same as a lamp. You would expect to see strange colours, in different directions. I suspect that your flash is so much brighter than the desk lamp, that you just aren't seeing it.

20mm. Hmm, as you're using micro 4/3, that might not need to be a retrofocus design ( no mirror to miss). Which would be good

Retrofocus wideangles usually aren't wonderful, reversed.
But you ARE getting chromatic aberration (CA) in the pics above. Look hard (magnify in your browser, even) at the sharp detail towards the edges. You'll see the same colour fringes towards the centre of the image in all cases, and the opposite colour towards the edge.

f10 on the lens. OK. What's the magnification on to the sensor? About 3x?
If so, that's an effective aperture of f(3+1) x 10 = 40.
If you look at diffraction, here
http://www.cambridgeincolour.com/tutori ... graphy.htm, you'll see that you're losing definition at that aperture. I think your sensor is about the same numbers as the Nikon D2X - I'll leave you to dig it out. Click Nikon D2X then end run your mouse up and down the aperture column. Smaller than about f11 effective aperture, and you'll get fuzz coming in. Though it wouldn't show on the 1024 wide pics on the forum, at that level.

So, open the lens up. You'll have to experiment, but try f2.8 on the lens. Oh but you need depth of field!! Yes you do, it can be a compromise. If you start stacking your images, you can get your dof back that way.
Hopefully you'll also get less CA, you'll have to see.

The other thing you've found out is about lighting reflective subjects - it's downright HARD in macro, sometimes, to get enough diffusion. Things like that lens cap will be fairly difficult.

Keep at it, it's worth it, you'll have fun!

photosmart42 · Post by **photosmart42** » Sat Jan 23, 2010 8:45 am

lauriek wrote: Shots look technically quite nice. Not sure about the dof. Can you stop the lens down when it's reversed? (I notice you mention shot at f10, but does the lens actually stop down when not attached directly to the camera?)

Thank you! I can't stop down the lens after it's reversed, so I have to decide what DoF I want ahead of time, fix the lens at that f-stop while on the camera normally, then freeze that f-stop and take the lens off. I was actually surprised how shallow the DoF was even at f/10.

photosmart42 · Post by **photosmart42** » Sat Jan 23, 2010 9:05 am

ChrisR wrote:You'll get a lot of support and encouragement on this forum, so allow me to toss some negativeish comments in! Hope you find them constructive.

Thank you! I have a thick skin, and I'm here to learn, so constructive criticism is always welcome =).

ChrisR wrote:You're mixing your desk lamp (filament bulb??) with flash. Flash is approximately = daylight, but not the same as a lamp. You would expect to see strange colours, in different directions. I suspect that your flash is so much brighter than the desk lamp, that you just aren't seeing it.

I was using the desk lamp primarily as a source of lighting to allow me to focus correctly. I figured it would be washed out, although I have some non-flash shots with just the desk lamp that came out OK once I increased the ISO and reduced the shutter speed appropriately. I played around with the intensity of the flash to get me the correct lighting at the settings I wanted (ISO 100 and 1/160 shutter speed). I also played around a bit with the positioning of the reflector to see what effect it'll have on the shadows. All in all it was a very useful learning session for lighting.

ChrisR wrote:20mm. Hmm, as you're using micro 4/3, that might not need to be a retrofocus design ( no mirror to miss). Which would be good Retrofocus wideangles usually aren't wonderful, reversed.
But you ARE getting chromatic aberration (CA) in the pics above. Look hard (magnify in your browser, even) at the sharp detail towards the edges. You'll see the same colour fringes towards the centre of the image in all cases, and the opposite colour towards the edge.

I'll have to look closer. I'm not actually sure what to look for in terms of color fringes. As far as CA is concerned, I can't tell the difference between CA and just teh organic nature of the subject I was shooting (the shavings), although it might be easier to tell in the shot of the hard lens cap. I don't have a trained enough eye to see that stuff yet, so thank you for pointing it out.

ChrisR wrote:f10 on the lens. OK. What's the magnification on to the sensor? About 3x?
If so, that's an effective aperture of f(3+1) x 10 = 40.
If you look at diffraction, here
http://www.cambridgeincolour.com/tutori ... graphy.htm, you'll see that you're losing definition at that aperture. I think your sensor is about the same numbers as the Nikon D2X - I'll leave you to dig it out. Click Nikon D2X then end run your mouse up and down the aperture column. Smaller than about f11 effective aperture, and you'll get fuzz coming in. Though it wouldn't show on the 1024 wide pics on the forum, at that level.

I haven't figured out the magnification yet. The actual height of the 'L' in the Lumix photo is 4.8mm, and the same dimension on the image takes up about 5mm on my sensor, so I'm looking close to at a 1:1 conversion with that lens for my sensor. My effective sensor size is 17.3mm x 13mm (4/3), and the photo was taken at 4000 x 3000 (4:3 format). It's just about 2.0 crop factor from FF. Looks like according to the link you posted (thanks!!), I'd want to be around f/5.6 for optimum resolution on my lens/sensor.

ChrisR wrote:So, open the lens up. You'll have to experiment, but try f2.8 on the lens. Oh but you need depth of field!! Yes you do, it can be a compromise. If you start stacking your images, you can get your dof back that way.
Hopefully you'll also get less CA, you'll have to see.

I've started playing around with stacking a bit, and plan to do more. I may have to invest in a better focusing rail since the cheap one I got is a bit rough step-wise. I could try to modify the existing one to make it smoother. I also don't have the budget to buy something like ZS right now, so I'll have to figure out stacking in PS.

ChrisR wrote:The other thing you've found out is about lighting reflective subjects - it's downright HARD in macro, sometimes, to get enough diffusion. Things like that lens cap will be fairly difficult.

Yes, it was! The specular reflection off that metallic text gave me some headaches. I had to turn the power of the flash all the way down to 1/16, point it to the ceiling, and play around with the distance of the reflector from the image until I got something that wasn't so 'sparkly'. I'm building a DIY diffuser for my flash, so that'll help soften the light as well.

ChrisR wrote:Keep at it, it's worth it, you'll have fun!

Thank you. I had a lot of fun doing this little shoot, and learned a ton!

ChrisR · Post by **ChrisR** » Sat Jan 23, 2010 9:50 am

CA - see your second shot, lower right corner, black pieces of lead.
They have a blueish fringe on the left and red on the right.

photosmart42 · Post by **photosmart42** » Sat Jan 23, 2010 10:11 am

ChrisR wrote:CA - see your second shot, lower right corner, black pieces of lead.
They have a blueish fringe on the left and red on the right.

Ah, yes, now I see it. Had to look at the 1:1 photo. Definitely seeing the color fringing around the black lead granules now. Thanks!

So color fringing is how CA shows up in photos? I thought CA had something to do with bending what should be straight lines, although the 'chromatic' part of it should have told me it's related to color. Is the bending of straight lines called something else then?

ChrisR · Post by **ChrisR** » Sat Jan 23, 2010 10:59 am

Are you thinking of pincushion/barrel distortion? Or Spherical Aberration?
Hit Google, there's a ton of good info on things like this.
If you're blighted by CA, try something like Photoshop or whatever, also try cropping the pic. It sounds like heresy but the middle 3MP of your frame would be enough for a good A3 print!

DO have a try with a stacker, even with a very crude setup. Hand-held will do even, see some of LordV's amazing work here. (Easy after the first 40 years or so of experience...

)
Zerene is popular here partly because Rik produced it ( and it's getting better, creep creep), partly because it's darned good, but there are others. CombineZM is free and works fine. Again Google, "Focus Stacking software".

photosmart42 · Post by **photosmart42** » Sat Jan 23, 2010 12:34 pm

ChrisR wrote:Are you thinking of pincushion/barrel distortion? Or Spherical Aberration?
Hit Google, there's a ton of good info on things like this.

Will do. For some reason I thought CA and spherical aberration were the same, but I now realize that's silly. I'll have to research these different effects more.

ChrisR wrote:DO have a try with a stacker, even with a very crude setup. Hand-held will do even, see some of LordV's amazing work here. (Easy after the first 40 years or so of experience... )
Zerene is popular here partly because Rik produced it ( and it's getting better, creep creep), partly because it's darned good, but there are others. CombineZM is free and works fine. Again Google, "Focus Stacking software".

Thank you - I'll give that a shot. I don't mind paying for quality tools eventually, but it'll have to wait for the moment. I'll see what I can find for free =).