Tubelens

I have been building a DIY microscope (see Pic.) for digital holography. I was wondering if there are any downsides to not using a tube lens to relay the field to the sensor in conjecture with a water immersion infinity corrected objective? I know that without using the tube lens the working distance is now changed (slightly more than before) and keeping the sensor closer to the objectives decreases the magnification.PS: I see distortions when I image 1 micron sulfate beads, possibly due to a tilt in the sensor.