Lemming51

When in Av mode, what is the aperture displayed in the camera? Presumably it is the phony "1.4" or whatever from the adapter chip. Is the 40D "fooled" and allowing you to dial in an aperture number ...

as I asked before, "... Include the model #s of the Godox and Yongnuo speedlites, ..." Some manual slave speedlites are "digital" and ignore the low-powered TTL metering pre-flash of many/most ...

maybe better asked in the Studio and Lighting Technique forum. Include the model #s of the Godox and Yongnuo speedlites, and sample pics with ISO and aperture settings you're using in M. If the ...

Thanks.. You have a link? ;-)

Maybe keep using the f/2.8L, but transfer the weight to a monopod?  (traditional or the kind that stand on their own).

By chance, are your VELLO wireless triggers connected to the PC Sync port of your 1Ds III? Maybe your "very used 1Ds III" has a well worn, loose, or faulty hotshoe? Otherwise ... you should not ...

In fairness, the OP did end his/her post with "I'm confused." ;)

(1) Built-in flash popped-up, at least partly?  The built-in cannot do high speed sync, so if the camera thinks it's active it'll limit the shutter speed to 1/250 and slower.

Nice, almost an infrared effect. ... But what's going on with the clouds in this one (and the gray outline of the lighthouse)?

+1 https://cpn.canon-europe.com/content/education/technical/latest_ef_lens.do?page=2 " Canon has used Fluorine coatings on the low-pass filter in front of its CMOS sensors in all of its recent EOS ...

While I think keeping firmware current is a good practice, why is this a "must"? Support for a couple other lenses is listed among the fixes in the latest firmware, but not the RF 24-105 f/4-7.1 ...

Not normal. 1936 x 1288 is the S (small) jpg size. RAW is always the full 3888 x 2592. Some bodies have smaller sized M-RAW and S-RAW choices, but not the XS/1000D. You're sure it's the xxxxx.CR2 ...

https://www.bhphotovideo.com/c/product/1546031-REG/canon_3924c002_eos_rebel_t8i_dslr.html listed as In Stock for the kit with 18-55 lens.  body only is "Coming Soon".

Custom controls, C.Fn III-4, pp. 497-504 in the instruction manual. specifically p. 502, you can switch the assignment of the dials for shutter speed and aperture in M mode.

Good luck with that. ;) There aren't any new EF lenses that are priced higher than the same in RF, much less used. RF 24-105 f/4-7.1 IS STM = $400 (EF 24-105 f/ 3.5-5.6 IS STM = $600 is not equivalent)

(a) Check that the speedlite is fully in the hotshoe and tightened. (b) Check that the flash head is pointed straight ahead and level (should feel click-stops at this position).  If it is angled ...

Make sure the AF mode in Live View is either FlexiZoneAF or FaceDetection and not AFQuck.  AFQuick uses the same AF sensors as viewfinder shooting, which requires the mirror to drop down briefly, ...

+1. The 40D takes CF card.  Get one of those. https://en.wikipedia.org/wiki/CompactFlash (illustrations only, not meant as an edorsement of any particular brands) The SD card is smaller and cannot ...

Apologies, I stand corrected.

? Sounds like the camera told you exactly what the problem was.  It's also noted in the instruction manual:  "Built-in flash settings is not available when an external flash is attached."  That's ...