DPReview.com is closing April 10th - Find out more

RF35mm f/1.8 IS STM MACRO AF performance.

Started 3 months ago | Discussions thread
Martin_99 Veteran Member • Posts: 4,631
Re: RF35mm f/1.8 IS STM MACRO AF and Resolution performance.
1

bharathmsk wrote:

Thanks @Martin_99. Please find the answers below.

1. You are looking at 100% magnified photos in the center.

2. I use the electronic levels to judge horizontal and vertical tilts of the camera. I also used a laser distance measurer from the target to check distances of the camera from the target. The images I had attached were taken at about 2 ft. All results were reproducible at ~4ft, ~8ft.

3. Thank you for the note on decentering. I have never done this before. I will check this.

Given 1 and 2, any thoughts on the results? Thank you!

Martin_99 wrote:

bharathmsk wrote:

Thanks all.

@Martin_99, following your link to opticallimits, I read through the review and I had some hope instilled in me. I repeated the resolution chart experiments (attached pictures, I have concatenated images, use Dpreview loupe).

On what are we looking at actually? 100% magnified photos in center?

To my dismay, the lens gets sharpest at f/11-f/16! And the resolution drop from f/1.8 -> f/2.8, f/4 and the recovery thereafter at around f/5.6 is also very clear. These results were highly reproducible.

Hard to judge. If somebody tell me such result, my first thought is user testing error. What is your distance from target? Are you sure that camera is perpendicular to test chart?

So the lens is poorer than I had originally thought (I should have taken the time to sweep through the entire aperture range). At this point, I certainly feel like this lens is a lemon. And the poor optical performance could have lead to a poor AF performance like the opticallimits review indicate. I think I should contact the manufacturer. If you all have other insights to add, please, I would greatly appreciate them!

What I mostly do - testing decentering based on below link:

https://phillipreeve.net/blog/how-to-check-how-decentered-your-lens-is/

Conclusion is not allways easy though.

To answer your question @Martin_99 on the AF settings, when I photograph family, these are left at eye tracking & servo. For these resolution chart pictures, they were left at single point AF on the target.

RF 35mm f/1.8 IS STM MACRO

Thank you for your help and support!

I would wait for your decentering test results.

Additional question - what ISO was set on this set of photos?

Nevertheless I believe that even you have subpar copy, you will most probably not see it on your images. But for your peace of mind, if it will be confirmed, return it.

 Martin_99's gear list:Martin_99's gear list
Sony a6400 Sony Carl Zeiss Sonnar T* E 24mm F1.8 ZA Sigma 56mm F1.4 DC DN | C (X-mount) Sony E 70-350mm F4.5-6.3 G OSS Tamron 150-500mm F5-6.7 Di III VC VXD +1 more
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow