Optical Resolution on the EF-S 18-55 mm lens

[PolyJet]

Hello! I am a researcher using an EF-S 18-55 mm lens to film some mechanical testing of composite structures I have 3D printed using a polyjet printer and I was wondering if anyone knows the dpi on this lens or has tested it? The points I am tracking are 0.1 mm apart.

Thank you!

[johnrmoyer]

There have been several EF-S 18-55mm lenses. https://en.wikipedia.org/wiki/Canon_EF-S_18%E2%80%9355mm_lens 

Your question about dpi cannot be answered as you asked it. Please first identify which lens you have. Next you will need the size of the sensor chip and the spacing of photosites on the chip.

The capture resolution will vary with:

• distance to subject
• focus distance
• small aperture diffraction blur
• modulation transfer function of the lens
• spacing of photo sites on the sensor chip
• scene lighting
• vibration of camera tripod
• distortion from imperfections or mis-alignment of lens elements
• distortion resulting from lens design tradeoffs

For one of the EF-S 18-55 lenses, there is a (modulation transfer function) MTF chart at: https://personal.canon.jp/product/camera/ef/ef-s18-55-f4-56is-stm/spec  , but there are charts only for 18mm and 55mm and not for other focal lengths.

I suggest reading https://www.cambridgeincolour.com/tutorials/lens-quality-mtf-resolution.htm  or https://www.usa.canon.com/learning/training-articles/training-articles-list/reading-and-understandin...  for an introduction to the subject. There is something with a little more detail at: https://arxiv.org/abs/1805.01872 Cite as: arXiv:1805.01872 [cs.CV] (or arXiv:1805.01872v1 [cs.CV] fo... 

Also, https://www.science.gov/topicpages/m/modulation-transfer+function+mtf.html 

[kvbarkley]

Here is a take on how diffraction affects things:

https://www.bobatkins.com/photography/technical/diffraction.html

Also, the 18-55 can have a lot of distortion which might be an issue for you.

https://kenrockwell.com/canon/lenses/18-55mm-f4-56-stm.htm#perf

I suggest a 100mm macro.

It is only available used, but the EF-S 60mm macro would be good for this.

You can also check out the EF-S 35 mm macro, but it has some distortion at far distances.

Here is a way to practically check the resolution for yourself with some supplied charts:

https://bobatkins.com/photography/technical/lens_sharpness.html

[ebiggs1]

" I was wondering if anyone knows the dpi on this lens ..."

First and foremost let's clear this up. Lenses do not have DPI. Printers have DPI. Not even a camera has DPI. Although you may hear someone speak of DPI associated with their camera. They are confused.

You want to know the resolution of your lens which is very complicated matter. As some have stated above other factors are more important. Any of the 18-55mm lenses Canon makes are intended for the basic consumer market and buyer. Thus they are in that category regarding their IQ (resolution).

However what may be more important is what camera you choose. You probably should be looking for a very high  pixel count sensor model.