Advice needed. Tabletop with Digaron 180S or 138mm Float

[nicoswartz]

Hi All, I'm going to shoot a tabletop series, and I'm looking for advice..
The setting will be 50cm high, and I've shot it previously on an SK BR 150mm / IQ4
It's all in a controlled light environment.

I have the following options:
>> (Rent) a IQ4 150 and keep my Rodenstock Digaron-S..
Do you guys think the Digaron 180mm will be better than the SK BR 150? (I don't need to tilt or shift the lens)

>> Buy a CVF100 and keep my Rodenstock Digaron-S..
I'm wondering what the crop factor will do. 180mm x 1.3 is getting probably too close?

>> But a CVF100 & buy the Rodenstock 138mm
I'm really curious if you'll see a big difference in detail in comparison with the 180 setup..

Last but not least: Buy an older IQ3100 instead of the new CFV 100?
it's all so controlled, I'm curious if you see a big difference sensor wise.

 

[Paul Spinnler]

What magnification are you aiming at for your tabletop series? The 138 is good as long as you don't do macro or close to it, ie within its minimum focusing distance; for macro / low mag. the 120 BR or 105 HR Float are a better choice.

I’d need to check the MTF sheet - but with the 138 it’s key to stay within the intended range, ie above minimum focusing distance according to Rosenstock’s documentation.

 

[daz7]

50 cm objects are large enough for you to use any lens you like as you will be working at 1:10--1:15 scales.
Digarons are excellent for that type of magnification ratios and hr180 reaches its optimal characteristics at 1:12 scale. I am also certain it should be better than 150mm BR lens as it is hard to beat digarons for anything between 1:10-1:30.
For scale lower than 1:5 you can use any good macro lens and for scales from 1:5-1:10 I am a big fan of enlarger / copy lenses.
Also, 138mm should be better than any normal lens from 1:5 scale upwards.
138 gives you a slight edge over 180hr and is probably the most universal lens you can get but it's price is still a bit obscene.

 

[nicoswartz]

Very interesting!! Where do you find the information about the optimal scale for the 180?
To be honest I don't understand the 1:10 scale idea.. Does it 1:10 mean? Is it 10 times the height of the sensor?
And do you know the optimal scale for the 138?

 

[dchew]

Nico,
@cunim had a similar near-field application. I sent him a raw file from about 1 meter. I will look for the files. But I warn you, he bought it after seeing the file.

Dave

 

[cunim]

The 138 is superb for tabletop down to just below 1 m distance. Magnification is a bit too low for watches but fine for cutlery (for example). A big part of the goodness lies in the outer areas of the image circle. The 138 is cleaner than most other lenses as you apply movements. WIth a typical combination of tilt and swing it blows away my 120 apo macro sironar. For me, buying the 138 to use with the IQ4 was a great decision.

But there are negatives (weight, cost, complexity), and ultimate resolution is not usually a key issue. in tabletop Unless you need substantial movements, other lenses can be fully adequate. Also, because so much of the benefit of the 138 comes from its clean outer IC, I would be unlikely to pair this lens with a crop sensor. Why bother? Not knowing your specific requirements renting the IQ4 seems the rational business decision. That is unless you really want the 138.

 

[Paul Spinnler]

Mag 1:10 means you project an object ten times the size onto the sensor; mag 1:1 is one to one, meaning a large coin for example in the middle of the IQ4 sensor.

Macro is typically defined at 1:2 or 1:1 and below. As soon as you approach low magnifications you are better off with macro lenses.

Performance degrades as soon as you go below the minimum focusing distance.

The 105 was markedly better than the 138 in negative scanning for example although I thought the 138 would obliterate the 105. It didn’t as I was using it below its intended range.