CS lenses and shutter lag (vs non CS lenses)

[Slender]

Advertisement (gone after registration)

Dear fellow S shooters. hi! I need your help of knowledge on this topic.

DOES USING CS LENSES, even when setting the S camera to FPS mode, CAUSES SHUTTER LAG vs using the simpler non CS lenses?

I have set my sights (for some time) on the S system to complement my SL2 and M10R camera systems. I will defo get into it as prices are very attractive and I do miss the OVF experience since my R8 days and have been a bit frustrated by some of the quirks of the SL2, mostly poor battery life and a weird reaction to my Leica SF24D flashes at times.

In order to get a system as different from the SL and M, getting CS lenses would make sense for what I intend to do with it as I find myself enjoying flash with M, SL and Q (same principle with central shutter) a lot lately.

However I got a message of warning from an S user on the French Leica Forum that goes as follows (translated)

 

"I use three CS lenses, among others, on an S 007 camera since 2018: the 35mm, the 70mm, and the 180mm, to shoot with flash above 1/125th, especially the 180mm, which is unusable in low light without stabilization (you get camera shake as soon as you get below 1/180th), so flash is mandatory if you're not in broad daylight on the 180mm. With the 35mm and the 70mm, you can go down to 1/50th handheld without flash. 

You immediately feel with these CS lenses that the kinematics of the lens's iris opening and closing and that of the camera's shutter curtain combine! So you experience a slight lag between the moment you press the shutter button and the moment the sensor is exposed, which you don't experience with non-CS lenses, especially the 70mm non-CS, which I end up using more than the CS. It's a lag of less than a second, but it's there, and it doesn't exist on my non-CS lenses. The reason is quite simple: On a DSLR like the S 007, when you use a CS lens, the camera's shutter curtain must open BEFORE the lens's iris, which then takes over by synchronizing with your flash... and you feel a slight difference in responsiveness compared to shooting with the camera's shutter alone. So I'll adjust my comment: it has no impact on the photos, because unless you're shooting extremely fast subjects in front of you, you're not going to miss your shot because of it. And since burst shooting is anecdotal on the S, you won't feel like your CS lens is less responsive when you use the central iris.

It's the shutter release that's really different from what you get with a non-CS lens. Unless you're working with flash in a studio, for example. To get started with an S, and to buy used lenses, I recommend starting with non-CS lenses, especially the 70mm and 35mm, which are easy to find on the market without breaking the bank. If you do a lot of portraits, save money and get the 100mm S f/2.0, which only comes in a non-CS version and is, in my opinion, THE BEST medium format lens on the market, of any brand! Does this gap exist when these CS lenses are mounted on an SL? Apparently yes, since these SL cameras still have a classic mechanical shutter. We'll have to test it in real life to be sure... Don't hesitate to ask if you have any further questions."
 

I am very puzzled by the way he formulates his answer 😅 I can definitively conceive the whys and hows for a slight shutter lag when using CS lenses WITH the CS camera mode because the mirror has to flip up, the lens iris and CS need to close, then the FPS need opening for the OPEN/CLOSE cycle of the CS... then FPS closes again, mirror falls downs, CS and IRIS open fully again. Agreed, understood.

HOWEVER, shouldnt this sequence get much simpler (Mirror up -> Iris closes -> FPS opens&closes -> Mirror down -> iris opens) when setting the camera to FPS mode, even when having a CS lens mounted? Therefore negating any lag induced by the CS/FPS dance compared to when setting the camera to CS mode? 

Or does the leaf shutter in the lens still plays a part of the dance, even when using the camera on FPS mode? Hence creating a difference with non-CS lenses?
 

I just need clarification because for intended use I envision 40/60 usage of the lenses (40% CS and 60% FPS)... so if CS lenses have cripple the shutter lag even in FPS mode that could be a deciding factor for me.

Many thanks to the community!


 

[Stef63]

This (French) post mainly reflects personal opinions that are not supported by solid technical knowledge. The author undermines in the end his entire argument by stating that CS lenses are “apparently” slower on the SL as well.  There is no CS functionality possible on the SL as this camera has not enough power to drive the CS.  So what would cause delay vs non CS versions as the CS is open all the time.

Furthermore, the CS-mode sequence is not executed in a strictly sequential manner. When the mirror flips up, the central shutter can close at the same time (even faster than the mirror because it can open close in 1/1000s) and the focal plane shutter can open simultaneously to minimize any delay. Also suggesting that the CS adds delay in FPS mode without any technical explanation why that would be is also pure speculation.

P.S. Claiming that the Summicron-S 100 is the “money saving” option is again a very subjective opinion.

Edited April 6 by Stef63

[davidmknoble]

I’ll be more direct.  I have many of both.

Using the CS lenses in the focal plane shutter mode have exactly the same lag from shutter press to photograph.  The central shutter is always in the open mode, so it causes no delay.

Using the central shutter also has no lag.  The focal plane shutter opens and then the central shutter closes as the appropriate time completing the image.  Thus, there is no delay between the focal plane and central shutters. In both cases, the mirror goes up and the first shutter curtain opens. The potential minute delay between the shutter opening fully before the central shutter can close vs. a slit in the shutter is too small to worry about.

I use them both in all modes with no problems.

[Slender]

Many many thanks to you @davidmknoble and @Stef63! I was 95% sure of what you say but I was somewhat thrown sideways by that user report! I appreciate it a lot.

@davidmknoble I followed your post and your website. I imagine I would use an S equally with flash for fine art/staged images as for landscape and nature. May I ask you how do you find yourself balancing between your use of CS or FPS, also why if I may ask, would you have versions of both lenses for the same focal length?

 

 

[Stef63]

Interesting article by David Farkas on Red Dot Forum :

“What’s interesting to note in the sequence is that the exposure starts electronically. This allows for a simpler movement by only having the central shutter close to end the exposure rather than open and close.”

[davidmknoble]

@Slender There isn't so much use of a central shutter for landscape work as in flash work.  I do have CS and non-CS lenses of the same focal length, but that is mostly because the prices have come down so much.  I enjoy shooting flash outside with family and friends and inside for special family events.    

I will sometimes use the CS lens for landscape with the sun in the image, but it doesn't seem to have the same effect as a Hasselblad lens.  If you don't want to use flash much, then the non-CS lenses are less expensive and the same image quality.  The article @Stef63 points to is an excellent discussion of lenses and the flash capabilities of CS lenses.

 

[epines]

Advertisement (gone after registration)

I have five S lenses on the S3, all of them CS. In FPS mode, there's no lag between shutter press and capture. In CS mode, it's always seemed to me that there is a very slight lag, maybe 1/4 second. When you shoot in CS mode, there's an additional sound that's not there in FPS mode, and truthfully I don't know exactly when the capture is made during the sequence of sounds. But it does seem that the duration between pressing the shutter and the shot appearing on the display is very slightly longer in CS mode than in FPS mode, implying that the capture is made very slightly later. 

Let me add that the S3 and its lenses are phenomenal. I use the system as my main workhorse, my go-to for everything. See ethanpines.com if you want to see examples. 

 

 

Edited April 8 by epines

[davidmknoble]

@epines I shoot regularly at a 1/4 to 1 second  range with the CS lenses using the central shutter. The lag is microseconds if there is one. The sound is very different. See my post above. The focal plane shutter opens and the sensor begins recording. At the end of the shutter speed the central shutter closes. It is not like the hasselblad where the cs closes then opens and the closes again. The lag is no more than the time it takes to open the focal shutter. 

[Slender]

14 hours ago, epines said:

 

Let me add that the S3 and its lenses are phenomenal. I use the system as my main workhorse, my go-to for everything. See ethanpines.com if you want to see examples. 

 

 

This is a great and encouraging addition, thank you very much Ethan! I am answering from a mobile device right now but I will check it asap I am super keen to have feedback from Pros, always!

[Slender]

21 hours ago, epines said:

Let me add that the S3 and its lenses are phenomenal. I use the system as my main workhorse, my go-to for everything. See ethanpines.com if you want to see examples.

Wow I am Blown away Ethan. Well done you Mister that is one heck of a portfolio for range and quality.... bravo! Most of them made with S3 or you had other systems/previous S cameras as well?

Regardless that matters very little in truth.... thats one badass website and career you have there! Awesome, and I feel gratefull you dropped by to help with your message!

 

[epines]

1 hour ago, Slender said:

Wow I am Blown away Ethan. Well done you Mister that is one heck of a portfolio for range and quality.... bravo! Most of them made with S3 or you had other systems/previous S cameras as well?

Regardless that matters very little in truth.... thats one badass website and career you have there! Awesome, and I feel gratefull you dropped by to help with your message!

 

Thank you, very much appreciate that. I'd say about 1/3 of the site was done with the S3 (roughly the first 1/3 of each gallery, since those are the most recent). You can also tell by looking at the aspect ratio, unless I've cropped it, which I sometimes do. The rest of the site was mostly done with a Leaf Credo 60 back on a Hassy H4x body. Plus some before that with a Hassy H5D50 system. 

I still have the Credo 60 + H4x. I always like having a backup medium format, and it's still a very good system, worth much more to me than on the open market. (That back also works very nicely on the Alpa.) But the Leica S has been a great step forward. Flash sync up to 1/1000; focal plane shutter up to 1/4000; weather sealing; 3.5 FPS if you want it; single battery that lasts forever; giant OVF (I find that shooting mirrorless feels like I'm looking at a video monitor rather than at the subject / composition, although I imagine I'd get used to it over time); best lenses I've ever used in terms of sharpness, color, contrast and draw / rendering; consistency across all lenses; fast maximum apertures; fantastic ergonomics; smart and simple menus; gorgeous styling; an overall user experience that feels solid, thoughtful and refined. I also feel like the S3 has more improvements over the 007 than people give it credit for: 64MP, 8-min maximum exposure, cleaner high ISO (some kind of dual-gain technology), very clean long exposures, better color, 4K video using the entire sensor width, and anecdotally better focusing. 

[davidmknoble]

@epines very nice work with the central shutters. It’s always nice to see how differently people use the system.  I especially like your editing style that seems (in some portfolios) like older color film.  Thanks for sharing your work!