My motivation for considering the 20-70mm is for pairing it with the A7CR for a lightweight travel kit.
When reading another thread comparing these two lenses, some thought that they needed the f/2.8. I believe that in a minority of images, many of us need f/2.8, but why? For me it comes down to bokeh and ISO. My argument here assumes that relatively few images actually require f/2.8. What I’m proposing is that where you might need the GM II, you supplement your 20-70mm G with “AI”. My comments here are with regards to Lightroom and Photoshop. The judicious and subtle addition of AI blur and ISO/Noise Enhanced images would allow for the lighter/smaller/better macro f/4.0 lens to part time substitute for the big brother GM lens. What do you think?
I have absolutely been exploring this idea recently. There's more testing to do, but when the blur tool is used subtly it can be very effective.
We can fight the AI and software advances and get left behind, or we can make the best use of these new tools. That's my opinion, anyway.
bwcolor wrote:
What I’m proposing is that where you might need the GM II, you supplement your 20-70mm G with “AI”. My comments here are with regards to Lightroom and Photoshop. The judicious and subtle addition of AI blur and ISO/Noise Enhanced images would allow for the lighter/smaller/better macro f/4.0 lens to part time substitute for the big brother GM lens. What do you think?
GMPhotography wrote:
Do take a look at the 24-50 as well as I have that on my A7CR and it’s a perfect lightweight kit.
This looks like another great travel lens that give up range for a wider maximum aperture. What I didn’t mention is that when traveling I regularly use a 21mm lens. This means that I would need to travel with two lenses, which is my M11 Monochrome kit for travel .. two lenses, but the lenses are much smaller. Currently, my light Sony kit.. as of ten minutes ago, is a Zeiss Loxia 21mm and the 40mm G lens.,
I’d go with the 20-70 for travel. You will definitely make use of the wider end on the 20-70. I find f2.8 zooms are in no man’s land for travel. They are typically heavy and bulky…yet only get you 1 stop over the f4 zooms. I’d take a 1.8 prime in the focal length you use the most for the times you need the faster aperture.
bwcolor wrote:
This looks like another great travel lens that give up range for a wider maximum aperture. What I didn’t mention is that when traveling I regularly use a 21mm lens. This means that I would need to travel with two lenses, which is my M11 Monochrome kit for travel .. two lenses, but the lenses are much smaller. Currently, my light Sony kit.. as of ten minutes ago, is a Zeiss Loxia 21mm and the 40mm G lens.,
The range of 20-70, especially on a a7rc (26mpx in camera crop) just can't be beat... effectively a 20-105 range. I have a 40G for backgrounds or lower light work. I might pick up a 90 2.8i to really blow out backgrounds. I do like what I see in terms of output from the 24-50. I think it's a different use case though. You'll want a wide lens to travel with it. I expect I'll get the 24-50 2.8 at some point and use it too.
This approach to purchasing lenses could also be applied to the 85mm f/1.4 GM. I sold my version 1 of the 85mm and 16-35mm GM. The new Sony II lenses are smaller, lighter and better than version 1, but they are still larger, heavier lenses where AI post processing might allow for lighter, smaller, but slower lenses.
I really don’t know how to approach the 24-50mm f/2.8g vs 20-70 f/4.0g. The 24-50mm is a bit shorter and ever so slightly lighter. No idea which one is optically superior, but of course the 24-50mm dominates at f/2.8 and the other lens dominates at the extreme focal lengths. The 24-50mm is parafocal and to me this is a big deal. I doubt that the 20-70mm is parafocal.
For travel I'm currently using the Tamron 17-28/2.8 and 28-200/2.8-5.6 on an A7Riv and typically the 18-135 on my A6400 or A6700. Looking back I'm far more likely to have considered stopping down some for depth of field than wishing I had shallower depth of field and separation.
Looking at our trip to Switzerland and the Rhine River Cruise, the 17-28 got a lot more use in the cruise side excursions. Old cities, cathedrals and especially interiors. Now in the 17-28 or 16-35 ranges, depth of field is already pretty deep if not working particularly close. I also used DxO, Topaz and Lightroom noise reductions afterwards in processing if I'd had to let ISO float in darker areas, night shots, interiors, etc.
I, for my personal uses, don't see any reason that I would not consider an f4 zoom in use with the noise reduction software. I'm thinking about the 16-35/4 pz to get a bit better focal length range for walk arounds and the 20-70 might make a really useful "one lens" in some places instead of the 28-200. I'm not sure I'd leave the 28-200 and 16-35 or 17-28 behind completely on a major trip but in urban areas, the 20-70 could easily put the others into extended canvas carry time.
