MTF graphs
How do I reconcile older mtf graphs with more modern ones say to compare Olympus 14-150mm and 12-45mm?
Hi Catriona - I've asked our equipment editor, who carries out a lot of these lens tests and writes the reviews, to answer your question here in the thread - please be patient, it is a long weekend.
Quote:How do I reconcile older mtf graphs with more modern ones say to compare Olympus 14-150mm and 12-45mm?
A query from me - do you mean the manufacturers MTF - usually testing the lens in isolation without a body attached - or an MTF 50 graph which measures results with a lens attached to a body? An MTF 50 result is usually used for current lens tests on this site.
Olympus MTF information is at https://download.aws.olympus.eu/consumer/brochures/cameras/Lenses_LineUp_2019-04_Brochure_web_EN.pdf - and can reasonably be used to compare one lens with another from the same same manufacturer.
MTF 50 graph results partly depend on the MP of the body used for the test.
MTF is only one source of information useful for determening overall likely lens performance.
Quote:
Quote:How do I reconcile older mtf graphs with more modern ones say to compare Olympus 14-150mm and 12-45mm?
A query from me - do you mean the manufacturers MTF - usually testing the lens in isolation without a body attached - or an MTF 50 graph which measures results with a lens attached to a body? An MTF 50 result is usually used for current lens tests on this site.
Olympus MTF information is at https://download.aws.olympus.eu/consumer/brochures/cameras/Lenses_LineUp_2019-04_Brochure_web_EN.pdf - and can reasonably be used to compare one lens with another from the same same manufacturer.
MTF 50 graph results partly depend on the MP of the body used for the test.
MTF is only one source of information useful for determening overall likely lens performance.
I mean the graphs on the ephotozine site in the ephotozine reviews. Sorry if that wasn’t clear.
Quote:
I mean the graphs on the ephotozine site in the ephotozine reviews. Sorry if that wasn’t clear.
Thanks for clarifying this detail.
The results in an MTF graph similar to the ones used at ephotozine make it difficult to compare one result to another - unless obtained using the same camera body.
Results from a manufacturers "optical MTF" not using a body are relevant to any lens from that manufacturer.
This is explained in this article:
https://www.ephotozine.com/article/lens-reviews---find-out-how-we-review-lenses-33167
Thanks
Josh
https://www.ephotozine.com/article/lens-reviews---find-out-how-we-review-lenses-33167
Thanks
Josh
Thanks for the article but it doesn’t answer my query.
To be more simplistic what score of lw/ph corresponds to poor, fair, good, excellent as neither appears to directly correspond to the other?
To be more simplistic what score of lw/ph corresponds to poor, fair, good, excellent as neither appears to directly correspond to the other?
Regarding the 14-150mm review:
https://www.ephotozine.com/article/olympus-m-zuiko-digital-ed-14-150mm-f-4-5-6-lens-review-22983
This was tested on a 16mp Panasonic Lumix G3, and when tested the figures for MTF were deemed to be "Excellent" as shown in the graph. Unfortunately, we do not have the actual figures available, as that was not how we displayed our test results at the time.
We reviewed the 12-45mm lens with our new review procedure, where we display both the MTF figures from Imatest, and the description of whether it is "Excellent" or "Good" in the text above the graph:
https://www.ephotozine.com/article/olympus-m-zuiko-digital-ed-12-45mm-f-4-0-pro-review-34599/performance
This was tested on a 20mp Panasonic Lumix G9 so is not directly comparable.
https://www.ephotozine.com/article/olympus-m-zuiko-digital-ed-14-150mm-f-4-5-6-lens-review-22983
This was tested on a 16mp Panasonic Lumix G3, and when tested the figures for MTF were deemed to be "Excellent" as shown in the graph. Unfortunately, we do not have the actual figures available, as that was not how we displayed our test results at the time.
We reviewed the 12-45mm lens with our new review procedure, where we display both the MTF figures from Imatest, and the description of whether it is "Excellent" or "Good" in the text above the graph:
https://www.ephotozine.com/article/olympus-m-zuiko-digital-ed-12-45mm-f-4-0-pro-review-34599/performance
This was tested on a 20mp Panasonic Lumix G9 so is not directly comparable.
