7D Mark III plus EF 400/4 DO

Started 1 month ago | Discussions thread
OP Steve Balcombe Forum Pro • Posts: 13,634
Re: 7D Mark III plus EF 400/4 DO

Chris Mak wrote:

Steve Balcombe wrote:

No, I haven't posted in the wrong forum. I just wanted to announce that the cash for a 400 DO which I had budgeted for this year - to be bought when the 7D3 finally appears - has been reallocated to the fund for an R5 + RF 100-500L.

At least I think it has...

I briefly used the 400DOII with 1.4TC on the EOS-R. No compromise in functionality at all. So it will undoubtedly work seamless on the coming EOS-R5. But an EOS-R5 is full frame and will cost more than double of what a 7DIII would cost.

The idea is to put more cash into the body, with a less expensive lens, instead of more cash into the lens on the cheaper body. Total should be in the same ball park.

The RF100-500L will get awefully dark with a tc, so practically limited to 500mm. The 400DOII is still f5.6 at 560mm, and f8 at 800mm.

I wouldn't use a TC on the 100-500, just as I don't normally use a TC on my 100-400 now (maybe occasionally on the 5D4 but not on the crop bodies).

Please bear in mind I'm not necessarily looking for the most powerful option here - the R5 and the 400 DO together would break the budget, it has to be either/or. It's more a case of which is the best compromise, looking forward.

As a frequent bird photographer, the amount of detail I can record is important. Obviously the 600/4L IS III is going to trounce anything else, but here I'm looking for something smaller and lighter, and with the either/or proviso mentioned above. It's Friday evening with a wet weekend ahead, so I did a little calculation using that well-known metric of 'pixels/bird', based on a 10 cm subject at 4 metres. The number of (linear) pixels recorded for the 10 cm subject is as below. I'll start with the big lens just to give us a point of reference:

600 mm on 90D (my densest sensor) - 4682 pixels/bird.

600 mm on 5D4 (my favourite sensor) - 2800 pixels/bird

600 mm plus 1.4x on 5D4 (my regular big lens setup) - 3920 pixels/bird

Ok, moving on to possible smaller setups:

400 mm (100-400 or 400 DO) on 90D - 3121 pixels/bird

400 DO + 1.4x on 90D (same as 7D3?) - 4369 pixels/bird

400 mm on 5D4 - only 1867 pixels/bird but a very nice walk-around setup

400 mm + 1.4x on 5D4 (nice if it's a 400 DO, marginal if it's a 100-400) - 2613 pixels/bird

And last but by no means least, the new option:

100-500 at 500 mm on R5 (assuming 8100 x 5400 px) - 2812 pixels/bird.

I fully, 100%, totally understand that pixels/bird is not the be-all and end-all, it's just one part of the package. But 2812 px/b is a very long way short of the 4369 px/b that the 400 DO + 1.4x would achieve on a likely 7D3, and it's even 10% behind the 3121 of the bare 400 on the same sensor. Do I want to accept that trade-off against the undoubted benefits in other respects of the R5 with a dedicated RF mount telezoom?

So still hoping for a 7DIII, but it will 99% sure be mirrorless when it comes. The 5DV also turned out to be mirrorless.

For the life of me I can't work out what Canon is going to do with high-end crop. EOS M isn't up to the job, and there is not the slightest hint of a crop sensor RF mount body à la Nikon Z50. The 90D isn't a proper 7D3 substitute, but it could be Canon's way of keeping that segment ticking over for a while longer. What a waste of a cracking good sensor if it turns out to be a dead end.

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