Softness with finite objectives?

[Deanimator]

Images from my Amscope 4x and 10x finite objectives seem somewhat soft to me. I'm not sure I have enough experience to judge.

Could this be due to:

1. improper objective to sensor distance
2. reflections inside the bellows
3. something else

I'm pretty sure I've got a solid structure now, so I discount vibration.

For example, see the crop of the isopod taken with the 10x:



Is that what I should expect or am I doing something wrong?

Any advice would be appreciated.

[Troels]

I would start experimenting with better diffused light.
I see overexposed highlights. They are destructive and confuse the stacking program.

[ChrisR]

Sorry to be a skeptic, but I'd be unable to discount vibration if it were mine, until I'd tried using flash for a few frames. It really is that hard to be rid of, I found.

You've probably already looked for internal reflections - eyeball from the rear end of the bellows, aiming at a bright light. Can you see anything except darkness, other than from the objective itself? Any rings of light or bellows ridges lit up, will reduce the contrast and make the image look less sharp.

Remind us, what's the camera and how are you using it, shutter-wise?

As you say, the lens is "unproven". Certainly the Nikon 10x NA 0.3, which used to be the gold standard, is sharp. Not millimeter-critical to tube length.
I have a couple spare, as does Chris S!

[Deanimator]

Sorry to be a skeptic, but I'd be unable to discount vibration if it were mine, until I'd tried using flash for a few frames. It really is that hard to be rid of, I found.

That image was shot with a studio strobe on 1/16 (the lowest) power.

You've probably already looked for internal reflections - eyeball from the rear end of the bellows, aiming at a bright light. Can you see anything except darkness, other than from the objective itself? Any rings of light or bellows ridges lit up, will reduce the contrast and make the image look less sharp.

I didn't but I didn't really know how until you just described it.

Remind us, what's the camera and how are you using it, shutter-wise?

1. Canon T4i
2. Amsscope 10x on bellows
3. 1/200 shutter speed at 100 ISO
4. Flashpoint studio strobe at 1/16 power through a styrofoam cup

As you say, the lens is "unproven". Certainly the Nikon 10x NA 0.3, which used to be the gold standard, is sharp. Not millimeter-critical to tube length.
I have a couple spare, as does Chris S!

I'll try out your suggestions, probably, this weekend and report back.

I'll pull the camera and shine one of my 300w equivalent CFLs on the bellows to see if there are any leaks.

I just switched from horizontal mode used for the isopod to vertical mode. I'm still working on the diffusion from that. The diffuser (styrofoam) tends to interfere with the movement of the camera assembly.

Thanks for your help.

[ChrisR]

Sorry I thought it was continuous light for some reason.

You could try rear curtain flash synch at the end of say a 2 second exposure in the dark. That might help if the mirror /shutter vibes are a problem. Seems unlikely at 1/16th power though.
The room doesn't have to be all that dark - as long as you get a black image without the flash.

[ztt74]

Interested to see if you make any progress on this - my setup is near identical, with the exception of the objective (lomo 3,7 or Nikon 10x). I also get quite soft images out of it. I was wondering whether live view being on at the time of capture was impacting it, but I dont think so.
I just received a Godox AD-S17 diffuser recommended by Beatsy in this thread to see if the improved lighting will help when a faster shutter speed is used.

[kaleun96]

My first step would be internal reflections as what you're seeing is similar to what I saw when I first started out with a finite objective setup. If it is indeed a problem, you won't need to do a stack to work out whether you've mitigated the reflections or not. When I first installed flocking inside my extension tubes, it was night and day difference in the image quality.

Diffusion should help prevent light bouncing off the specimen (or anything in front of the lens) and back into the lens but this doesn't seem like it's entirely caused by lack of diffusion. I even tend to find that over-diffusing light leads to softer images with lower contrast.

How does the 4x look?

[Deanimator]

Update:

1. I removed some extraneous hardware from my bellows. They came with an attachment for slide copying and I didn't realize that what that mounted on was unnecessary for normal use of the bellows. That greatly reduced the lever arm moment on the rig.
2. I took a stack of a small screw from an Arca Swiss plate. It seems sharper.
3. Now that the rig has less structure to interfere with diffusion materials, I need to look at a more permanent diffusion rig for vertical use.
4. Does anyone have a suggestion for a good subject for testing the sharpness?

A tight crop on the threads of the screw:

[mawyatt]

A semiconductor (silicon) wafer is hard to beat and you can find them on eBay for very little.

Best,

[ChrisR]

Spatter from laser-printed paper is pretty good, too.

[ztt74]

It seems that increasing the shutter speed has helped for me (e.g. to 1/3200 or above). This is difficult to do with the foam cup as a diffuser because it cuts out a lot of light but easy when using the Godox AD-S17 diffuser. Using Lomo 3,7...

pictures of unknown bug:

1/4000 shutter, 1/4 power flashpoint

1/320 shutter, 1/8 power flashpoint

1/4000 shutter, 1/4 power flashpoint - 100% crop

1/320 shutter, 1/8 power flashpoint, 100% crop

[Deanimator]

I'm not getting enough sleep [which I already knew].

The last thing I shot was with the 10x, not the 4x.

I'm currently shooting an around 100 image stack of a small luggage key using the 4x, at 1/320 with the strobe at 1/2 power and the styrofoam diffuser.

We'll see what happens. At least in focusing, it seems pretty sharp.

We shall see.

They're supposed to inspect my smoke detectors (at no fixed time), while a full suite of construction equipment is at work next door, actually shaking the whole apartment. It literally sounds like the Battle of Prokhorovka, minus the shooting. I have to get up this evening so that I can work all night. <sigh>

[rjlittlefield]

The insect is a Lace Bug, https://en.wikipedia.org/wiki/Tingidae .

About this...

Canon T4i ... 1/4000 shutter, 1/4 power flashpoint

I'm having a bit of trouble understanding exactly how that works.

When the Canon T4i is set on 1/4000 shutter, the exposure is made by a thin band of sensitivity, 1/4000 second wide, that still takes about 1/250 second to slide clear across the sensor.

So if the T4i really is implementing 1/4000 second, the light pulse must last at least 1/250 second in order to incrementally expose the whole sensor.

That can be done with a flash that supports FP sync mode, which makes the actual light output be an extended series of very rapid low power flashes, in total spanning more than 1/250 second.

But I'm not aware that the Flashpoint studio strobes support FP mode.

Can somebody explain to resolve my confusion?

--Rik

[Deanimator]

Here's the ~3/4" luggage key.
Shutter: 1/320
ISO: 100
Strobe: 1/2 power



A tight crop:

[ztt74]

Rik,
Not sure how qualified I am to answer your question. I do have HSS activated though if that provides any useful insight, and the Flashpoints are operating through an R2 MarkII TTL transmitter.
Frankly, lighting has been the biggest struggle I have come up against; I spent quite a bit of time reading posts here trying to find a solution and hoped that the Flashpoints would be an upgrade tot he Janso lights I have been relying on. Any tips on improving my game here would be welcomed!
Jon