Zeiss SFL 8x40 vs 8x30

[JoeK]

Can anyone who has compared these side by side advise on this?
8x30 @ 16oz 8x40 @ 22oz
I’ve heard regarding similar comparison of swaros NL/EL options that weight concious folks maybe happy with the smaller objective and only be giving up on performance right at the first/last minutes of light and the smaller objectives are toe to toe the rest of the day.
But are we talking the last 5-10min or 30-45min?
Specs list 6ft greater FOV on the 30mm which is negligible.
These will be for chest binos on archery hunts and paired with a larger tripod bino for extended glassing and picking apart country.
I’m may be willing to take 6ozs of glass into the backcountry for 30 min of low light performance but if the difference is only noticable 5-15min maybe I’d go light on my chest and free up weight for the companion tripod binos and MAYBE even tote a compact spotter…
hopefully some 14x52NL’s will come into my life one day.
Anybody speak to this issue overall or these specific binos?
Thanks!

 

[blkqi]

To put it simply, the 40mm will exceed the performance of the 30mm whenever your pupil dilates larger than 3.75mm.

 

[JoeK]

Certainly. However I’ve never measured my pupils and I don’t have any clue at what light intensity that occurs…

 

[blkqi]

No one will be able to provide an adequate answer to your question. This varies by individual and depends on genetics, age, etc.

 

[gr8fuldoug]

Your timing is perfect as the Zeiss SFL's just went on $300.00 off sale

 

[Fritz D]

Not tried the 40 mm objective SFLs but I have the 8x30 version of same. I love it. I’ll never look at compact binos the same way?
Physics being what it is, I can only imagine the 8x40 will be even better-with everything save the increased mass?

 

[texasbbq]

Your timing is perfect as the Zeiss SFL's just went on $300.00 off sale

This has to be or right at the best deal going in optics today.

 

[Quandary]

I have the 8x40. Worn in a chest harness. They are so light I barely notice them.

 

[JoeK]

I opted for 8x30 figuring at first light I’m likely to have a set of larger binos on a tripod anyways and then I can enjoy the smaller and lighter form factor on my chest until dusk when I may be giving up a little performance. Notwithstanding any replies comparing the two on this thread I may still end up ordering a pair of 8x40 and comparing them side by side myself…

 

[JoeK]

Not tried the 40 mm objective SFLs but I have the 8x30 version of same. I love it. I’ll never look at compact binos the same way?
Physics being what it is, I can only imagine the 8x40 will be even better-with everything save the increased mass?

From what I’ve seen on optics comparisons and heard on a couple of podcasts the two may be nearly identical in optical performance until, as blkqi stated, your pupil dilates beyond the 3.75 exit pupil of the 30mm. But smaller and lighter in the hand has a real advantage with a bow in one hand.

 

[JoeK]

I compared the 8x32 SFL and 8x40 SFL and for very little size/weight penalty I found the 40's to be all around brighter and easier to glass with. I have not had a chance to look through the NL 32's but I am sure they are great glass and would serve you well especially for archery season.

^from the 10x32 NL thread which is addressing the same basic points of 30/32mm vs 40/42mm binos though with a distinct context for the other OP.

Really gonna be hard now not to just get my hands on the 8x40s and run my own side by side comparison.

 

[HOCM60]

I have had them both and unless weight and compact size are your number one priorities, I would get 8x40. The 8x40 is brighter especially in low light like in a wooded area or under canopy and most importantly eye placement is much easier and less finicky with the bigger exit pupil, and you will get way fewer blackouts.

The 8x40 also has less glare than the 8x30 if that is important to you. The 8x40 SFL is a small light binocular anyway, and it is an excellent all around binocular. I really liked the color purity it has say compared to a Zeiss FL which often times has a green tint. The only reason I sold mine is to get an even bigger aperture.

 

[JoeK]

I've been viewing with the 8x30's for a couple of weeks and am dang impressed with these. they are incredibly clear and crisp and the featherweight is super comfortable to hold up. I'm going to pick up the 8x40's on current sale and see what I gain at low light as I can certainly tell when the light is fading and the exit pupil starts limiting. It's doesn't seem to drop off until maybe the last 15 minutes or so of shooting light. I just have to put the 8x40 side by side and do my own comparison.
I can't imagine wanting to add ANOTHER 8oz past the 8x40 (14oz beyond the 8x30, nearly double the weight) to step even farther into the new 8x50. So far most of the input has recommended the 40's over the 30's so maybe 8x40 will be my huckleberry.

 

[nphunter]

I’ll be curious what you find out. I just picked up some NL 8x32’s to complement my NL14’s. I’ll most likely pack both NL’s and my spotter when deer hunting or going into the high country for elk.

The 8x32’s are great so far, they are only about 2oz less than the Razor 10x42’s I’ve carried for years but I’m liking the image and great depth of field.

I’ve never really understood the last light argument, seeing a few minutes earlier is for sure great but IMO last light is irrelevant since you need to be able to either get to that animal or find it in a rifle scope. If your in those last few minutes of fading light that a bigger objective is going to matter than you’re probably not getting a shot anyway. I have used my 10’s to find bucks I couldn’t see with my 15’s, the exit pupil was 3.8mm in the 15’s and 4.2mm with the 10’s.

I was very happy with the low light performance of the 10x42 Razor. I could pull them up to my eyes at dusk and see much more than with the naked eye. With the 15’s it was the opposite, the image would darken vs my eyes. I haven’t tested this with the NL’s yet, if they don’t work out I also think the jumping to a bigger size isn’t a big deal. I’d be looking at about 8oz and going from a 4mm to 5.2mm exit pupil. Everything I’ve read on birding forums it says there is no noticeable difference in real world glassing at dusk between the two.

I don’t really understand how the whole exit pupil and twilight rating cross over to field use, I just experiment with different glass and see what works for me.

 

[Eagleye]

In this case, I’m inclined to think most of our eyes can’t see the difference well enough to make a difference in a hunting situation. Optics marketing teams have us all chasing the next greatest product!

 

[JoeK]

So far I'm not convinced the 8x40 is worth the weight over the 30's. But I'm an ounce counting backpacker so 6oz on my chest all day and in my hands is significant...
There is clearly a difference in brightness between the two but after several dawn/dusk sessions side by side and birdwatching in the yard the difference is most notable during the first/last 20-25min of light and really I'd say only during the last 7-10 minutes or so will the 40mm allow me to effectively keep glasssing when the 30's have dropped off. During brighter conditions I can still notice the difference in brightness going back and forth but they both look great. If one is working in dark timber then the 40's would be worth it for sure. Around here in South AZ where I'm mostly in open desert terrain brightness is not usually something I need MORE of until dusk. As I mentioned in the OP these for me will be a companion bino and a set of 50-56mm on the tripod are in the pack for picking apart hillsides and peering into the shadows looking to spot game in the landscape.
I can really tell the difference for about 25 min as the 40's start to pull away with brighter and better image, but for about half that time the 30's are still doing fine. I think the weight will end up the deciding factor for me in this comparison. 30's are definitely giving up some optical performance, but really not a big functional difference outside of those final minutes of light when I'm hopefully closing in for a shot or probably scanning through the big binos anyways.

I do also notice the eye relief of the 40's is more forgiving and the 30's can be a little finicky by comparison, eyeglass users that could be a big deal, my dad pointed it out right away. for me it's no problem, but it's there.
I do also prefer the SIZE of the 40's in my hand. The 30's are actually a little too small for optimal comfort in the hand and if you have large hands probably just stick with the 40's. I may have slightly smaller than average hands as I can be in between medium and large gloves. I love the featherweight aspect, but If the 30s were any smaller it would tip the equation for sure.

wait I thought I was convinced I like the 30's and now that I've typed this all out I'm kinda back on the fence. Do I really want to cut weight on my binos of all places? giving up optical performance to cut 6ozs? going around in circles, they're both really nice, great value, and I can't choose wrong either way.