Spring is slowly coming to the Oregon coast range (very slowly, its still snowing a bit) but my pond is starting to thaw out. I found a few paramecia and let them grow out in a jar with some hay infusion, and found quite a few conjugating. Apologies in advance for the bits of background filth/noise. My microscope needs a good spring cleaning. I even found a cat hair in the camera adapter after the new cat got into the scope room...after I'd taken the pictures. But I thought I'd post these anyway. All shots taken with a UplanApo 40/0.85 objective, and Variozoom/0.32X lens relay to a D300, with flash right through the halogen lamp to approximate Koehler conditions. All shots taken using DIC. Some shots were divided by a background image, some not, all retouched using imageJ.
Chris, these photos were taken using a BX-60, with a UDP40 lower nomarski prism, a UPlanApo 40/0.85 objective, standard U-DICT upper prism, then a Leitz Variozoom (5-12X) zoom eyepiece and the corresponding Leitz 0.32X lens which is built into the D300 adapter. Flash was provided by a SB-800 placed behind the halogen lamp in a modified ULH100 lamphouse and operated in remote command mode, so when the D300's internal flash fires the SB-800 is also triggered.
Yup, a little north of you up here in WA as well.... the rain is now 42 degrees F instead of 39
But the longer days do make one want to get out and take some new samples.
The DIC looks excellent here. Have you tried any A:B comparisons on a non-mobile subject between flash (as you have it implemented) and "factory" halogen illumination? I'd be curious if you find any visible differences (outside of color balance of course).
I have "eyeballed" the illumination uniformity for my improvised flash vs the halogen lamp source. I should really take a blank image with each light source, normalize them and plot the actual intensity surface for both to really make a quantitative statement. Something for the Equipment Discussion forum. So without a proper study I can only say that using the Mk I eyeball detector, the uniformity with the lamp and the flash are roughly equivalent, especially considering that DIC background illumination can be slightly nonuniform to start with. Same for brightfield as well. This is on the BX-60. With the Orthoplan I have a better (pretty much exactly Koehler) setup for the flash and lamp, since each can use a separate port on the multi-mirror housing. There I can't see any difference. On the BX I just modified the lamp house by removing the top portion (there's no optics in there on a ULH-100-3 at least) and sat the flash behind the lamp with some heat blocking glass to protect the flash from being overheated by the lamp (still have to run the lamp only at low settings). I am going to mill out a precise slot and holder into the lamp house in the near future. But for a typical Koehler setup, with the flash diffuser on, the distance from the "lamp" to the back of the condenser lens is not crucial. I will do some blank images and plot them up for the equipment discussion. Right now I am just enjoying the fact that my pond has thawed out and creatures are beginning to reappear. Even found some planaria recently.